{"id":10435,"date":"2022-02-15T09:32:22","date_gmt":"2022-02-15T08:32:22","guid":{"rendered":"https:\/\/zoccaratoverniciature.it\/en\/?p=10435"},"modified":"2022-02-16T08:34:06","modified_gmt":"2022-02-16T07:34:06","slug":"pretreatment-processes-for-coating-differences-between-degreasing-and-pickling","status":"publish","type":"post","link":"https:\/\/zoccaratoverniciature.it\/en\/pretreatment-processes-for-coating-differences-between-degreasing-and-pickling\/","title":{"rendered":"Pretreatment processes for coating: differences between degreasing and pickling"},"content":{"rendered":"<div id=\"themify_builder_content-10435\" data-postid=\"10435\" class=\"themify_builder_content themify_builder_content-10435 themify_builder\">\n    \t<!-- module_row -->\n\t<div   class=\"themify_builder_row module_row clearfix module_row_0 themify_builder_10435_row module_row_10435-0 tb_dvgd335\">\n\t    \t    <div class=\"row_inner col_align_top\" >\n\t\t\t<div  class=\"module_column tb-column col-full first tb_10435_column module_column_0 module_column_10435-0-0 tb_6bks335\">\n\t    \t    \t        <div class=\"tb-column-inner\">\n\t\t    <!-- module text -->\n<div  class=\"module module-text tb_l0ki336    \">\n            <div  class=\"tb_text_wrap\">\n        <\/div>\n<\/div>\n<!-- \/module text -->\n<!-- module text -->\n<div  class=\"module module-text tb_atxj336    \">\n            <div  class=\"tb_text_wrap\">\n    <p><em>Pre-treatment processes for coating are essential to ensure that the surface is perfectly clean and free of impurities. There are different types of pre-treatment, each with its own characteristics, and the difficult thing is to assess which is the best in each case. In the following article we will analyse two of the main methods of surface preparation: degreasing and pickling.<\/em><\/p>    <\/div>\n<\/div>\n<!-- \/module text -->\n    <!-- module divider -->\n    <div  class=\"module module-divider tb_5gio336 solid   divider-custom divider-left\" style=\"border-width: 1px;border-color: #ee2312;margin-top: 20px;margin-bottom: 20px;width: 710px;\">\n\t            <\/div>\n    <!-- \/module divider -->\n<!-- module text -->\n<div  class=\"module module-text tb_2vy3337    \">\n            <div  class=\"tb_text_wrap\">\n    <p><strong>Index<\/strong>:<\/p>\n<ul>\n<li><a href=\"#sgrassaggio\">What is degreasing<\/a><\/li>\n<li><a href=\"#decapaggio\">What is pickling<\/a><\/li>\n<li><a href=\"#differenze\">Differences between degreasing and pickling<\/a><\/li>\n<\/ul>    <\/div>\n<\/div>\n<!-- \/module text -->\n    <!-- module divider -->\n    <div  class=\"module module-divider tb_1sz4337 solid   divider-custom divider-left\" style=\"border-width: 1px;border-color: #ee2312;margin-top: 0px;margin-bottom: 20px;width: 710px;\">\n\t            <\/div>\n    <!-- \/module divider -->\n<!-- module text -->\n<div  class=\"module module-text tb_jblg337    \">\n            <div  class=\"tb_text_wrap\">\n    <p>Surface <strong>decontamination<\/strong> is a step in the coating process that should not be underestimated: its use ensures that an article is perfectly capable of receiving a surface finish treatment, avoiding possible negative repercussions caused by calamine, oils or oxides.<\/p>\n<p>\u00a0<\/p>\n<p>There are a number of methods for carrying out this stage, the main ones being degreasing and pickling. In the following article we will try to understand what these pre-treatments consist of and how they differ.<\/p>\n<p>\u00a0<\/p>\n<p><a name=\"sgrassaggio\"><\/a><\/p>    <\/div>\n<\/div>\n<!-- \/module text -->\n    <!-- module image -->\n    <div  class=\"module module-image tb_hmue338  image-top  \">\n\t                <div class=\"image-wrap\">\n                            <img decoding=\"async\" src=\"https:\/\/zoccaratoverniciature.it\/wp-content\/uploads\/2022\/01\/cataforesi-vasca-alcalina-zoccarato-1500x700-2.jpg\" width=\"710\" alt=\"alkaline degreasing tank\" \/>            \n                        <\/div>\n            <!-- \/image-wrap -->\n        \n                    <div class=\"image-content\">\n                \n\t\t                    <div class=\"image-caption tb_text_wrap\">\n                        An artefact is immersed in our alkaline degreasing tank                <\/div>\n                <!-- \/image-caption -->\n                            <\/div>\n            <!-- \/image-content -->\n        \n        <\/div>\n    <!-- \/module image -->\n<!-- module text -->\n<div  class=\"module module-text tb_ytma338    \">\n            <div  class=\"tb_text_wrap\">\n    <h2 style=\"color: #000000; font-size: 28px; font-weight: normal; line-height: 1.3;\">What is degreasing<\/h2>\n<p>Degreasing is a practice that involves <strong>removing grease, oil, grease and dirt from the metal surface<\/strong>. As already mentioned, it is an essential step in the search for perfect treatments: working on an impure surface would result in the application of a coating that is easily removable or does not adhere perfectly to the substrate. There are two types, solvent-based or water-based..<\/p>\n<p>\u00a0<\/p>\n<h3 style=\"color: #000000; font-size: 22px; font-weight: normal; line-height: 1.3;\">Solvent degreasing<\/h3>\n<p>Solvent degreasing is a practice that involves the use of solvents to clean metal surfaces. Over the last few decades it has undergone major changes, especially from an <strong>environmental perspective<\/strong>; many compounds that could be used until a few years ago have since been banned because they are harmful to the ozone layer and because of their high risk of flammability.<\/p>\n<p>\u00a0<\/p>\n<p>Since its application requires a lot of solvent and is not easily automated, nowadays it is mainly used for <strong>manual cleaning<\/strong> of specific greasy or oily parts for further processing.<\/p>\n<p>\u00a0<\/p>\n<h3 style=\"color: #000000; font-size: 22px; font-weight: normal; line-height: 1.3;\">Degreasing in the aqueous phase<\/h3>\n<p>Currently the most widespread and high-performance method in industrial painting, the so-called <strong>aqueous degreasing<\/strong> can actually be broken down into several different categories and classifications:<\/p>\n<ul>\n<li><strong>Classification by chemical type<\/strong>: perhaps the most widely used classification, it includes acid, neutral, alkaline and emulsion degreasers.<\/li>\n<li><strong>Classification according to the system<\/strong>: this categorisation concerns the way in which contact between solution and article takes place, which can be by immersion, spray, pressure lance and others.<\/li>\n<li><strong>Classification according to the accelerant<\/strong>: in this case there can be high\/low temperature, electrolytic and ultrasonic degreasers.<\/li>\n<\/ul>\n<p>\u00a0<\/p>\n<div style=\"width: 1165px; \" class=\"wp-video\"><video class=\"wp-video-shortcode\" id=\"video-10435-1\" width=\"1165\" height=\"655\" preload=\"metadata\" controls=\"controls\"><source type=\"video\/mp4\" src=\"https:\/\/zoccaratoverniciature.it\/wp-content\/uploads\/2013\/07\/vasca-alcalina-zoccarato.mp4?_=1\" \/><a href=\"https:\/\/zoccaratoverniciature.it\/wp-content\/uploads\/2013\/07\/vasca-alcalina-zoccarato.mp4\">https:\/\/zoccaratoverniciature.it\/wp-content\/uploads\/2013\/07\/vasca-alcalina-zoccarato.mp4<\/a><\/video><\/div>\n<p><em>In the video, the artefacts come out of the alkaline degreasing tank of our e-coating plant.<\/em><\/p>\n<p>\u00a0<\/p>\n<p>The process by which impurities are removed from the metal surface by immersion in aqueous solutions is carried out by means of <strong>emulsion<\/strong>. The degreasing solution, e.g. contained in a degreasing tank, has a lower surface tension than water due to the presence of tensoactives, which leads to the removal and detachment of oils and greases from the surface to be cleaned.<\/p>\n<p>The tensoactives are responsible for decreasing the interfacial tension that exists between the water and a certain article that comes into contact with it.<\/p>\n<p>\u00a0<\/p>\n<p>In addition to these, there are so-called <strong>builders<\/strong> (e.g. soda, silicates and carbonates) in the solution, which <strong>determine the pH and aggressiveness<\/strong> towards metal surfaces. The correct dosage of these elements is crucial for the correct execution of the degreasing process, as this process should not corrode the metal surface, should not compromise its aesthetics and should positively influence subsequent coating treatments.<\/p>\n<p><a name=\"decapaggio\"><\/a><\/p>    <\/div>\n<\/div>\n<!-- \/module text -->\n    <!-- module image -->\n    <div  class=\"module module-image tb_39rp339  image-top  \">\n\t                <div class=\"image-wrap\">\n                            <img decoding=\"async\" src=\"https:\/\/zoccaratoverniciature.it\/wp-content\/uploads\/2022\/02\/metallo_1500-x-700.jpg\" width=\"710\" alt=\"cataforesi operatori impianto\" \/>            \n                        <\/div>\n            <!-- \/image-wrap -->\n        \n        \n        <\/div>\n    <!-- \/module image -->\n<!-- module text -->\n<div  class=\"module module-text tb_yv3m339    \">\n            <div  class=\"tb_text_wrap\">\n    <h2 style=\"color: #000000; font-size: 28px; font-weight: normal; line-height: 1.3;\">What is pickling<\/h2>\n<p>Another technique related to the refinement of metal surfaces with a view to subsequent painting, pickling is a process by which surfaces are <strong>cleaned of oxides<\/strong>.<\/p>\n<p>\u00a0<\/p>\n<p>The <strong>chemical method<\/strong> called pickling is usually an <strong>immersion<\/strong> process, whereby the article comes into contact with a solution capable of eliminating surface oxides (calamine, laser oxides, etc&#8230;) resulting from the activities involved in creating the article, due to the high temperatures required to make the article itself.<\/p>\n<p>\u00a0<\/p>\n<p>Among the most commonly used acids are hydrochloric acid, sulphuric acid and hydrofluoric acid, which are also chosen according to the metal nature of the part to be treated (whether it is made of steel, titanium or aluminium, for example).<\/p>\n<p>When parts are de-oxidised by pickling, they easily undergo oxidation, even if only in contact with air. In order to prevent such oxidation, protective agents and\/or corrosion inhibitors are added to the pickling solution.<\/p>\n<p><a name=\"differenze\"><\/a><\/p>    <\/div>\n<\/div>\n<!-- \/module text -->\n    <!-- module image -->\n    <div  class=\"module module-image tb_gslp339  image-top  \">\n\t                <div class=\"image-wrap\">\n                            <img decoding=\"async\" src=\"https:\/\/zoccaratoverniciature.it\/wp-content\/uploads\/2022\/02\/vasca-pompe-1500-x-700.jpg\" width=\"710\" alt=\"automobili\" \/>            \n                        <\/div>\n            <!-- \/image-wrap -->\n        \n        \n        <\/div>\n    <!-- \/module image -->\n<!-- module text -->\n<div  class=\"module module-text tb_fp8t339    \">\n            <div  class=\"tb_text_wrap\">\n    <h2 style=\"color: #000000; font-size: 28px; font-weight: normal; line-height: 1.3;\">Differences between degreasing and pickling<\/h2>\n<p>Degreasing and pickling are often confused, sometimes even considered similar in industrial practice, when in fact they are two very different processes.<\/p>\n<p>\u00a0<\/p>\n<p>With degreasing, the cleaning process takes place mainly through emulsion, i.e. through contact between the article to be cleaned and the result of two or more liquids which, when shaken, do not mix homogeneously; in other words, the two components that characterise the mixture are distinguishable even after being combined, and it is these components that trigger the physical mechanisms that lead to the cleaning of the surface.<\/p>\n<p>\u00a0<\/p>\n<p>In the second case, that of pickling, real chemical reactions are induced, which lead to the disintegration of the oxides to be removed and, in part, also to the corrosion of the base surface (which is why corrosion inhibitors are required as &#8220;protectors&#8221;).<\/p>\n<p>\u00a0<\/p>\n<p>In terms of criticality, the two types of pre-treatment in question can present problems mainly linked to the effectiveness of the management of the industrial process. While <strong>degreasing is to be considered more flexible and harmless<\/strong>, as it has no etching capacity (i.e. the ability to remove part of the metal surface), <strong>pickling presents greater risks linked to the erosion action<\/strong> that can be triggered by the chemical phenomenon in the event of prolonged contact and\/or conduction parameters out of range.<\/p>\n<p>\u00a0<\/p>\n<p>Would you like to receive more information? Write to us at <a href=\"mailto:info@zoccaratoverniciature.it\">info@zoccaratoverniciature.it<\/a>.<\/p>    <\/div>\n<\/div>\n<!-- \/module text -->\n\t        <\/div>\n\t    \t<\/div>\n\t\t    <\/div>\n\t    <!-- \/row_inner -->\n\t<\/div>\n\t<!-- \/module_row -->\n\t<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Pre-treatment processes for coating are essential to ensure that the surface is perfectly clean and free of impurities. There are different types of pre-treatment, each with its own characteristics, and the difficult thing is to assess which is the best in each case. In the following article we will analyse two of the main methods of surface preparation: degreasing and pickling.<\/p>\n","protected":false},"author":2,"featured_media":10449,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2,1],"tags":[185,179,181,159,186,193,192,158,194],"class_list":["post-10435","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","category-senza-categoria","tag-cataphoresis","tag-ecoating","tag-industrial-coatings","tag-liquid-coating","tag-metal-surface","tag-phosphate","tag-phosphate-conversion-coating","tag-powder-coating","tag-zinc-phosphate","has-post-title","has-post-date","no-post-category","has-post-tag","has-post-comment","no-post-author",""],"builder_content":"<p>[smartslider3 slider=\"53\"]<\/p>\n<p><em>Pre-treatment processes for coating are essential to ensure that the surface is perfectly clean and free of impurities. There are different types of pre-treatment, each with its own characteristics, and the difficult thing is to assess which is the best in each case. In the following article we will analyse two of the main methods of surface preparation: degreasing and pickling.<\/em><\/p>\n\n<p><strong>Index<\/strong>:<\/p> <ul> <li><a href=\"#sgrassaggio\">What is degreasing<\/a><\/li> <li><a href=\"#decapaggio\">What is pickling<\/a><\/li> <li><a href=\"#differenze\">Differences between degreasing and pickling<\/a><\/li> <\/ul>\n\n<p>Surface <strong>decontamination<\/strong> is a step in the coating process that should not be underestimated: its use ensures that an article is perfectly capable of receiving a surface finish treatment, avoiding possible negative repercussions caused by calamine, oils or oxides.<\/p> <p>\u00a0<\/p> <p>There are a number of methods for carrying out this stage, the main ones being degreasing and pickling. In the following article we will try to understand what these pre-treatments consist of and how they differ.<\/p> <p>\u00a0<\/p> <p><a name=\"sgrassaggio\"><\/a><\/p>\n<img decoding=\"async\" src=\"https:\/\/zoccaratoverniciature.it\/wp-content\/uploads\/2022\/01\/cataforesi-vasca-alcalina-zoccarato-1500x700-2.jpg\" width=\"710\" alt=\"alkaline degreasing tank\" \/> An artefact is immersed in our alkaline degreasing tank\n<h2 style=\"color: #000000; font-size: 28px; font-weight: normal; line-height: 1.3;\">What is degreasing<\/h2> <p>Degreasing is a practice that involves <strong>removing grease, oil, grease and dirt from the metal surface<\/strong>. As already mentioned, it is an essential step in the search for perfect treatments: working on an impure surface would result in the application of a coating that is easily removable or does not adhere perfectly to the substrate. There are two types, solvent-based or water-based..<\/p> <p>\u00a0<\/p> <h3 style=\"color: #000000; font-size: 22px; font-weight: normal; line-height: 1.3;\">Solvent degreasing<\/h3> <p>Solvent degreasing is a practice that involves the use of solvents to clean metal surfaces. Over the last few decades it has undergone major changes, especially from an <strong>environmental perspective<\/strong>; many compounds that could be used until a few years ago have since been banned because they are harmful to the ozone layer and because of their high risk of flammability.<\/p> <p>\u00a0<\/p> <p>Since its application requires a lot of solvent and is not easily automated, nowadays it is mainly used for <strong>manual cleaning<\/strong> of specific greasy or oily parts for further processing.<\/p> <p>\u00a0<\/p> <h3 style=\"color: #000000; font-size: 22px; font-weight: normal; line-height: 1.3;\">Degreasing in the aqueous phase<\/h3> <p>Currently the most widespread and high-performance method in industrial painting, the so-called <strong>aqueous degreasing<\/strong> can actually be broken down into several different categories and classifications:<\/p> <ul> <li><strong>Classification by chemical type<\/strong>: perhaps the most widely used classification, it includes acid, neutral, alkaline and emulsion degreasers.<\/li> <li><strong>Classification according to the system<\/strong>: this categorisation concerns the way in which contact between solution and article takes place, which can be by immersion, spray, pressure lance and others.<\/li> <li><strong>Classification according to the accelerant<\/strong>: in this case there can be high\/low temperature, electrolytic and ultrasonic degreasers.<\/li> <\/ul> <p>\u00a0<\/p> <p>[video width=\"1920\" height=\"1080\" mp4=\"https:\/\/zoccaratoverniciature.it\/wp-content\/uploads\/2013\/07\/vasca-alcalina-zoccarato.mp4\"][\/video]<\/p> <p><em>In the video, the artefacts come out of the alkaline degreasing tank of our e-coating plant.<\/em><\/p> <p>\u00a0<\/p> <p>The process by which impurities are removed from the metal surface by immersion in aqueous solutions is carried out by means of <strong>emulsion<\/strong>. The degreasing solution, e.g. contained in a degreasing tank, has a lower surface tension than water due to the presence of tensoactives, which leads to the removal and detachment of oils and greases from the surface to be cleaned.<\/p> <p>The tensoactives are responsible for decreasing the interfacial tension that exists between the water and a certain article that comes into contact with it.<\/p> <p>\u00a0<\/p> <p>In addition to these, there are so-called <strong>builders<\/strong> (e.g. soda, silicates and carbonates) in the solution, which <strong>determine the pH and aggressiveness<\/strong> towards metal surfaces. The correct dosage of these elements is crucial for the correct execution of the degreasing process, as this process should not corrode the metal surface, should not compromise its aesthetics and should positively influence subsequent coating treatments.<\/p> <p><a name=\"decapaggio\"><\/a><\/p>\n<img decoding=\"async\" src=\"https:\/\/zoccaratoverniciature.it\/wp-content\/uploads\/2022\/02\/metallo_1500-x-700.jpg\" width=\"710\" alt=\"cataforesi operatori impianto\" \/>\n<h2 style=\"color: #000000; font-size: 28px; font-weight: normal; line-height: 1.3;\">What is pickling<\/h2> <p>Another technique related to the refinement of metal surfaces with a view to subsequent painting, pickling is a process by which surfaces are <strong>cleaned of oxides<\/strong>.<\/p> <p>\u00a0<\/p> <p>The <strong>chemical method<\/strong> called pickling is usually an <strong>immersion<\/strong> process, whereby the article comes into contact with a solution capable of eliminating surface oxides (calamine, laser oxides, etc...) resulting from the activities involved in creating the article, due to the high temperatures required to make the article itself.<\/p> <p>\u00a0<\/p> <p>Among the most commonly used acids are hydrochloric acid, sulphuric acid and hydrofluoric acid, which are also chosen according to the metal nature of the part to be treated (whether it is made of steel, titanium or aluminium, for example).<\/p> <p>When parts are de-oxidised by pickling, they easily undergo oxidation, even if only in contact with air. In order to prevent such oxidation, protective agents and\/or corrosion inhibitors are added to the pickling solution.<\/p> <p><a name=\"differenze\"><\/a><\/p>\n<img decoding=\"async\" src=\"https:\/\/zoccaratoverniciature.it\/wp-content\/uploads\/2022\/02\/vasca-pompe-1500-x-700.jpg\" width=\"710\" alt=\"automobili\" \/>\n<h2 style=\"color: #000000; font-size: 28px; font-weight: normal; line-height: 1.3;\">Differences between degreasing and pickling<\/h2> <p>Degreasing and pickling are often confused, sometimes even considered similar in industrial practice, when in fact they are two very different processes.<\/p> <p>\u00a0<\/p> <p>With degreasing, the cleaning process takes place mainly through emulsion, i.e. through contact between the article to be cleaned and the result of two or more liquids which, when shaken, do not mix homogeneously; in other words, the two components that characterise the mixture are distinguishable even after being combined, and it is these components that trigger the physical mechanisms that lead to the cleaning of the surface.<\/p> <p>\u00a0<\/p> <p>In the second case, that of pickling, real chemical reactions are induced, which lead to the disintegration of the oxides to be removed and, in part, also to the corrosion of the base surface (which is why corrosion inhibitors are required as \"protectors\").<\/p> <p>\u00a0<\/p> <p>In terms of criticality, the two types of pre-treatment in question can present problems mainly linked to the effectiveness of the management of the industrial process. While <strong>degreasing is to be considered more flexible and harmless<\/strong>, as it has no etching capacity (i.e. the ability to remove part of the metal surface), <strong>pickling presents greater risks linked to the erosion action<\/strong> that can be triggered by the chemical phenomenon in the event of prolonged contact and\/or conduction parameters out of range.<\/p> <p>\u00a0<\/p> <p>Would you like to receive more information? Write to us at <a href=\"mailto:info@zoccaratoverniciature.it\">info@zoccaratoverniciature.it<\/a>.<\/p>","_links":{"self":[{"href":"https:\/\/zoccaratoverniciature.it\/en\/wp-json\/wp\/v2\/posts\/10435","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/zoccaratoverniciature.it\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/zoccaratoverniciature.it\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/zoccaratoverniciature.it\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/zoccaratoverniciature.it\/en\/wp-json\/wp\/v2\/comments?post=10435"}],"version-history":[{"count":12,"href":"https:\/\/zoccaratoverniciature.it\/en\/wp-json\/wp\/v2\/posts\/10435\/revisions"}],"predecessor-version":[{"id":10448,"href":"https:\/\/zoccaratoverniciature.it\/en\/wp-json\/wp\/v2\/posts\/10435\/revisions\/10448"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/zoccaratoverniciature.it\/en\/wp-json\/wp\/v2\/media\/10449"}],"wp:attachment":[{"href":"https:\/\/zoccaratoverniciature.it\/en\/wp-json\/wp\/v2\/media?parent=10435"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/zoccaratoverniciature.it\/en\/wp-json\/wp\/v2\/categories?post=10435"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/zoccaratoverniciature.it\/en\/wp-json\/wp\/v2\/tags?post=10435"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}