{"id":1857,"date":"2014-08-29T09:42:25","date_gmt":"2014-08-29T14:42:25","guid":{"rendered":"https:\/\/advancedplatingtech.com\/?page_id=1857"},"modified":"2022-04-01T12:11:04","modified_gmt":"2022-04-01T17:11:04","slug":"plating-flake-loose-adhesion-plated-layer","status":"publish","type":"page","link":"https:\/\/advancedplatingtech.com\/technical-library\/plating-topics\/plating-flake-loose-adhesion-plated-layer\/","title":{"rendered":"What causes plating to \u201cflake\u201d or loose adhesion and what can be done to ensure proper adhesion of a plated layer?"},"content":{"rendered":"

\"\"<\/a>Adhesion is clearly paramount in both decorative and functional finishes.\u00a0 In situations where the adhesion of a plated deposit fails, the loss of adhesion is often blamed on the deposit itself.\u00a0 However, in most situations the proper adhesion of a plated deposit has little or nothing to do with the actual plated layer. The key to achieving good adhesion on any product is to ensure an\u00a0active\u00a0metal surface sufficiently void of oils, die releasing films, oxides, alloying inclusions and heat treat scale. \u00a0 Ensuring an active metal surface is the sole function of the pretreatment within a plating line.\u00a0 The pretreatment system on a plating line is composed of assorted and various alkaline presoaks, alkaline electro cleaners, acid pickles, deoxidizers, chemical descalers, ultrasonic cleaners, and activating strikes based upon the design and function of the plating line.<\/p>\n

All of the pretreatment systems listed above have a finite life within a plating line based upon the level and severity of usage as a function of the plating load and condition of plated product.\u00a0 If any one of the critical pretreatment chemistries looses its effective strength due to age on the line, poor adhesion of the end deposit can occur.\u00a0 Shown below are two examples of a plated deposit that lost adhesion due to a pretreatment system that failed to remove two common adhesion killers.\u00a0 Figure F.4 shows a lead inclusion on the surface of a 360 leaded brass part that was not removed in the pretreatment system.\u00a0 The result was a failed deposit that can be seen directly over the inclusion:<\/p>\n

Figure F.4:\u00a0 Loss of Adhesion due to Lead Inclusion at Surface<\/strong><\/p>\n

\"Loss-of-Adhesion\"<\/a><\/p>\n

Figure F.5 shows the surface of a heat-treated iron product that was plated over.\u00a0 Evidenced directly below the failed deposit is residual heat treat scale that was not removed by the pretreatment system.\u00a0 Often excessive heat treat scales can only be fully removed from the surface of a part by mechanical methods such as blasting or grinding prior plating. \u00a0\u00a0<\/strong><\/p>\n

Figure F.5:\u00a0 Failed Adhesion of a Deposit due to Heat Treat Scale<\/strong><\/p>\n

\"Failed-Adhesion\"<\/a><\/p>\n

Although proper maintenance and selection of pretreatment systems is the plater\u2019s responsibility, there are several key areas that buyers can assist the plater to successfully process their product.<\/p>\n

a.\u00a0 Provide the Exact Alloy of the Basis Material on all Paperwork including RFQs: \u00a0The specific alloy of a product can make a world of difference to the plater.\u00a0 For example 260 brass has no lead whereas 360 brass can contain up to 5% lead.\u00a0 Both brasses are very common in usage but each requires a very distinct pretreatment system to ensure proper activation.\u00a0 It is critical to provide the specific alloy UNS to the plater to ensure the parts are pretreated accordingly.<\/p>\n

b.\u00a0 Use less tenacious oils wherever applicable:\u00a0 Not all oils are created equal.\u00a0 Organic based oils derived from vegetable and animal sources are generally very easily removed from the surface of materials, whereas waxes and silicon based lubricates can be extremely difficult.\u00a0 The preference of oils used, in order of most preferred to least, is provided below.\u00a0 Whenever functionally and economically feasible, use a lubricant that is more \u201cplater friendly\u201d.\u00a0 Often extremely tenacious oils will require off-line degreasing to remove which can add considerable cost into the price of finishing a product.<\/p>\n