{"id":2654,"date":"2026-05-21T10:51:53","date_gmt":"2026-05-21T03:51:53","guid":{"rendered":"https:\/\/dk-metalsurfacetreatment.com\/?p=2654"},"modified":"2026-06-03T13:38:47","modified_gmt":"2026-06-03T06:38:47","slug":"white-rust","status":"publish","type":"post","link":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/white-rust\/","title":{"rendered":"Why Does a Brightly Shiny Zinc Plating Still Rust Over Time? How Does Passive Coating Address This Problem?"},"content":{"rendered":"<p data-rm-block-id=\"block-1\">In many metal processing factories, many businesses encounter a situation where the newly finished galvanized parts have a shiny surface, meeting aesthetic requirements, but after only a few weeks of storage or transportation, white rust spots have appeared. This not only affects the quality of the product but also increases the cost of warranty, reprocessing and reduces brand reputation.<\/p>\n<p data-rm-block-id=\"block-2\">According to metal surface treatment experts, the cause often does not lie in the quality of the galvanized coating but comes from ignoring or improperly performing the passivation stage \u2013 the final processing step that plays a decisive role in the corrosion resistance of the plating.<\/p>\n<h3 data-rm-block-id=\"block-3\"><strong>Why does shiny galvanized still rust?<\/strong><\/h3>\n<p data-rm-block-id=\"block-4\">Zinc is a metal with high chemical activity. As soon as the plating process is complete, the newly formed zinc surface will continuously react with oxygen, moisture, and corrosive agents in the environment.<\/p>\n<p data-rm-block-id=\"block-5\">In a hot and humid tropical climate like Vietnam, this reaction takes place quickly, creating the phenomenon of &#8220;white rust&#8221; \u2013 a white layer of zinc oxide or hydroxide that appears on the surface of the product.<\/p>\n<p data-rm-block-id=\"block-6\">Although the galvanized layer has the function of protecting the base steel by a &#8220;sacrificial corrosion&#8221; mechanism, if it is not protected by a passive film, this corrosion process will occur faster than expected, significantly reducing the product life.<\/p>\n<p data-rm-block-id=\"block-7\">In fact, many shipments of hinges, bolts or metal fittings that were not passivated appeared white rust after only a few weeks of storage. Meanwhile, products that are passively processed with the right process maintain their shine and corrosion resistance for months under the same storage conditions.<\/p>\n<h3 data-rm-block-id=\"block-8\"><strong>What is passivation and how does it work?<\/strong><\/h3>\n<p data-rm-block-id=\"block-9\">Passivation is a post-plating chemical treatment that creates an ultra-thin transition film on a metal surface.<\/p>\n<p data-rm-block-id=\"block-10\">This film acts as an &#8220;invisible shield&#8221;, preventing direct contact between the zinc coating and the external environment, thereby significantly slowing down oxidation and corrosion reactions.<\/p>\n<p data-rm-block-id=\"block-11\">In essence, during passivation, the zinc surface reacts with special chemical compounds to form a stable film, capable of:<\/p>\n<ul>\n<li data-rm-block-id=\"block-12\">Prevents moisture and oxygen from coming into contact with metal surfaces.<\/li>\n<li data-rm-block-id=\"block-13\">Limit the formation of white rust.<\/li>\n<li data-rm-block-id=\"block-14\">Increased corrosion resistance in harsh environments.<\/li>\n<li data-rm-block-id=\"block-15\">Maintain the shiny appearance of the product.<\/li>\n<li data-rm-block-id=\"block-16\">Increased service life for metal parts.<\/li>\n<\/ul>\n<p data-rm-block-id=\"block-17\">Thanks to this mechanism, the corrosion resistance of the product can be increased several times compared to ordinary galvanizing.<\/p>\n<p data-rm-block-id=\"block-18\"><strong>Economic and technical benefits of passive chemicals<\/strong><\/p>\n<p data-rm-block-id=\"block-19\">Nowadays, passivation is no longer considered an auxiliary stage but has become a mandatory requirement for many industries such as construction, mechanics, household electrical, automotive and industrial equipment.<\/p>\n<p data-rm-block-id=\"block-20\">Outstanding benefits include:<\/p>\n<p data-rm-block-id=\"block-21\"><strong>Enhanced corrosion resistance<\/strong><\/p>\n<p data-rm-block-id=\"block-22\">The passive film significantly extends the resistance time in salt spray tests, limits white rust and protects the surface during transportation and storage.<\/p>\n<p data-rm-block-id=\"block-23\"><strong>Increase product quality and value<\/strong><\/p>\n<p data-rm-block-id=\"block-24\">The product retains its shine longer, reduces the rate of defects and returns, and enhances the brand image.<\/p>\n<p data-rm-block-id=\"block-25\"><strong>Improve machining efficiency<\/strong><\/p>\n<p data-rm-block-id=\"block-26\">Some modern passivation systems also help reduce friction during the forming process, improve paint adhesion and support subsequent processing.<\/p>\n<p data-rm-block-id=\"block-27\"><strong>Responding to the trend of green production<\/strong><\/p>\n<p data-rm-block-id=\"block-28\">New technologies that use Chromium III or are completely Chromium-free help businesses meet increasingly stringent international environmental standards.<\/p>\n<p data-rm-block-id=\"block-29\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-2650 \" src=\"https:\/\/dk-metalsurfacetreatment.com\/wp-content\/uploads\/2026\/05\/ChatGPT-Image-15_18_35-17-thg-4-2026.png\" alt=\"\" width=\"697\" height=\"465\"><\/p>\n<h3 data-rm-block-id=\"block-30\"><strong>PRIMECOAT\u00ae Z838 \u2013 High-Performance Chromium III Passivation Solution<\/strong><\/h3>\n<p data-rm-block-id=\"block-31\">One of the solutions that is being chosen by many galvanized steel and galvanized steel manufacturers today is <strong>PRIMECOAT\u00ae Z838 \u2013 4P<\/strong> developed by AD International B.V (Netherlands).<\/p>\n<p data-rm-block-id=\"block-32\">The product uses\u00a0 advanced <strong>Cr\u00b3<\/strong><strong>\u207a (Chromium III)<\/strong> technology, which is\u00a0 completely free of toxic Chromium VI, which increases corrosion resistance while ensuring environmental safety.<\/p>\n<p data-rm-block-id=\"block-33\"><strong>Outstanding advantages of PRIMECOAT\u00ae Z838 \u2013 4P<\/strong><\/p>\n<ul>\n<li data-rm-block-id=\"block-34\">Increased corrosion resistance for galvanized steel, cold rolled steel and ZAM steel sheet.<\/li>\n<li data-rm-block-id=\"block-35\">Free of Cr\u2076\u207a v\u00e0 Fluoride.<\/li>\n<li data-rm-block-id=\"block-36\">Reduce friction during stamping and forming.<\/li>\n<li data-rm-block-id=\"block-37\">Improve the adhesion of paint and subsequent coatings.<\/li>\n<li data-rm-block-id=\"block-38\">Limit fingerprints.<\/li>\n<li data-rm-block-id=\"block-39\">Can be used flexibly for both Passivation and TOC depending on the coating thickness.<\/li>\n<li data-rm-block-id=\"block-40\">Supports the dry forming process effectively.<\/li>\n<\/ul>\n<p data-rm-block-id=\"block-41\">Thanks to its ability to combine corrosion resistance and fingerprint resistance, Z838 is becoming the right choice for many high-quality steel sheet manufacturers.<\/p>\n<h3 data-rm-block-id=\"block-42\"><strong>PRIMECOAT\u00ae Z908 VH \u2013 Completely Chromium-Free Passivation Technology<\/strong><\/h3>\n<p data-rm-block-id=\"block-43\">Besides the Chromium III solution, the trend of sustainable development is driving the demand for completely Chromium-free technologies.<\/p>\n<p data-rm-block-id=\"block-44\">In response to this requirement, AD International B.V has developed <strong>PRIMECOAT\u00ae Z908 VH,<\/strong> a line of phosphate-based and completely Chromium-based passivated chemicals.<\/p>\n<p data-rm-block-id=\"block-45\"><strong>Outstanding benefits of PRIMECOAT\u00ae Z908 VH<\/strong><\/p>\n<ul>\n<li data-rm-block-id=\"block-46\">Chrome-Free technology is environmentally friendly.<\/li>\n<li data-rm-block-id=\"block-47\">High corrosion resistance.<\/li>\n<li data-rm-block-id=\"block-48\">Effectively replacing traditional chromium passivation systems.<\/li>\n<li data-rm-block-id=\"block-49\">Maintains surface aesthetics even with thick coatings.<\/li>\n<li>Suitable for many modern galvanized steels such as:\n<ul>\n<li data-rm-block-id=\"block-50\">Galvanized Steel (Z)<\/li>\n<li data-rm-block-id=\"block-51\">Zinc Magnesium (ZM)<\/li>\n<li data-rm-block-id=\"block-52\">Galvalume (GA)<\/li>\n<li data-rm-block-id=\"block-53\">Aluzinc (AZ)<\/li>\n<li data-rm-block-id=\"block-54\">Electrolytic Zinc Plating (EG)<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p data-rm-block-id=\"block-55\">In the context of increasingly stringent environmental regulations, the Z908 VH is considered a solution to help businesses get closer to the goal of green production and sustainable development.<\/p>\n<h3 data-rm-block-id=\"block-56\"><strong>D.K Chemicals \u2013 a partner accompanying businesses in the field of surface treatment chemicals<\/strong><\/h3>\n<p data-rm-block-id=\"block-57\">In Vietnam, <strong>D.K Chemicals<\/strong> is a distributor and technical support of metal surface treatment product lines of AD International B.V (Netherlands).<\/p>\n<p data-rm-block-id=\"block-58\">With the orientation of bringing advanced surface treatment technologies from Europe to the Vietnamese market, D.K Chemicals provides a variety of solutions for the steel, aluminum and non-ferrous metals industries, especially in the fields of:<\/p>\n<ul>\n<li data-rm-block-id=\"block-59\">Passivation chemicals.<\/li>\n<li data-rm-block-id=\"block-60\">Anti-Finger Print Chemicals.<\/li>\n<li data-rm-block-id=\"block-61\">Chromium VI free surface treatment chemicals.<\/li>\n<li data-rm-block-id=\"block-62\">Solutions to increase corrosion resistance for galvanized steel and zinc alloys.<\/li>\n<\/ul>\n<p data-rm-block-id=\"block-63\">Not only providing products, D.K Chemicals also supports technical consulting, process optimization and accompanies businesses in the transition to safe, effective and environmentally friendly surface treatment technologies.<\/p>\n<p data-rm-block-id=\"block-64\"><strong>Conclusion<\/strong><\/p>\n<p data-rm-block-id=\"block-65\">A shiny galvanized coating does not mean long-term corrosion resistance. Without the passivation stage, the plating can still quickly appear white rust under the influence of moisture and the environment.<\/p>\n<p data-rm-block-id=\"block-66\">In the context of increasing quality requirements, the application of advanced passivation solutions such as <strong>PRIMECOAT\u00ae Z838 \u2013 4P<\/strong> and <strong>PRIMECOAT\u00ae Z908 VH<\/strong> not only helps to extend product life but also supports businesses to meet international environmental standards. This is an important step to improve product value,\u00a0 reduce maintenance costs and increase competitiveness in the modern metal industry.<\/p>\n<p data-rm-block-id=\"block-38\"><em><strong>Explore Some Surface Treatment Chemicals Here:<\/strong><\/em>\u00a0<a href=\"https:\/\/dk-chemicals.vn\/\" target=\"_blank\" rel=\"noopener\">https:\/\/dk-chemicals.vn\/<\/a><\/p>\n<p data-rm-block-id=\"block-39\"><em><strong>Explore Some of Our Other Products Here:<\/strong><\/em>\u00a0<a href=\"https:\/\/dk-metalsurfacetreatment.com\/san-pham-cong-ty-tnhh-hoa-chat-d-k\/\" target=\"_blank\" rel=\"noopener\">https:\/\/dk-metalsurfacetreatment.com\/san-pham-cong-ty-tnhh-hoa-chat-d-k\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>In many metal processing factories, many businesses encounter a situation where the newly finished galvanized parts have a shiny surface, meeting aesthetic requirements, but after only a few weeks of storage or transportation, white rust spots have appeared. This not only affects the quality of the product but also increases the cost of warranty, reprocessing<\/p>\n","protected":false},"author":9,"featured_media":2650,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[15],"tags":[554,552,547,548,549,553,550,544,546,545,551],"class_list":["post-2654","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news","tag-adchemiclas-en","tag-antifinger-en","tag-chrome3-en","tag-chrome6-en","tag-chromefree-en","tag-dkchemicals-en","tag-hoachatxulybematkimloai-en","tag-thudonghoa-en","tag-thudonghoachrome3-en","tag-thudonghoanonchrome-en","tag-xulybematkimloai-en"],"_links":{"self":[{"href":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/wp-json\/wp\/v2\/posts\/2654","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/wp-json\/wp\/v2\/users\/9"}],"replies":[{"embeddable":true,"href":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/wp-json\/wp\/v2\/comments?post=2654"}],"version-history":[{"count":5,"href":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/wp-json\/wp\/v2\/posts\/2654\/revisions"}],"predecessor-version":[{"id":3203,"href":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/wp-json\/wp\/v2\/posts\/2654\/revisions\/3203"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/wp-json\/wp\/v2\/media\/2650"}],"wp:attachment":[{"href":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/wp-json\/wp\/v2\/media?parent=2654"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/wp-json\/wp\/v2\/categories?post=2654"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/wp-json\/wp\/v2\/tags?post=2654"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}