The decisi­ve fac­tor is the cor­ro­si­vi­ty cate­go­ry to be achie­ved as well as the dura­ti­on of pro­tec­tion to be achieved

The fol­lowing docu­ment is inten­ded to pro­vi­de an insight into typi­cal pretre­at­ment and coa­ting opti­ons to achie­ve a required/suitable cor­ro­si­on pro­tec­tion. This matrix is to be unders­tood as a recom­men­da­ti­on only and in no way pro­vi­des a gua­ran­tee for achie­ving the desi­red pro­tec­tion category.

The qua­li­ty and thus asso­cia­ted pro­tec­tion dura­ti­on are stron­gly depen­dent on various fac­tors such as

• Qua­li­ty of the sub­stra­te (com­po­si­ti­on of the alloy)
• Qua­li­ty and imple­men­ta­ti­on of the pretreatment
• Qua­li­ty of the zinc coa­ting (thic­kness, passivation…)
• Selec­tion of pow­der coa­tings and app­lied coa­ting thicknesses
• con­struc­tion of the struc­tu­re (see con­struc­ti­ve mea­su­res cor­ro­si­on protection)
• Dama­ge of the paint surface
• etc.

Regu­lar pro­cess con­trol is the­re­fo­re essen­ti­al to pro­du­ce high qua­li­ty and long life.

The fol­lowing docu­ment is inten­ded to pro­vi­de an insight into typi­cal pretre­at­ment and coa­ting opti­ons to achie­ve a required/suitable cor­ro­si­on pro­tec­tion. This matrix is to be unders­tood as a recom­men­da­ti­on only and in no way pro­vi­des a gua­ran­tee for achie­ving the desi­red pro­tec­tion cate­go­ry.   (You can find the docu­ment here: Down­load)

The qua­li­ty and thus asso­cia­ted pro­tec­tion dura­ti­on are stron­gly depen­dent on various fac­tors such as

• Qua­li­ty of the sub­stra­te (com­po­si­ti­on of the alloy)
• Qua­li­ty and imple­men­ta­ti­on of the pretreatment
• Qua­li­tät der Ver­zin­kung (Dicke, Passivierung..)
• Selec­tion of pow­der coa­tings and app­lied coa­ting thicknesses
• con­struc­tion of the struc­tu­re (see con­struc­ti­ve mea­su­res cor­ro­si­on protection)
• Dama­ge of the paint surface

Regu­lar pro­cess con­trol is the­re­fo­re essen­ti­al to pro­du­ce high qua­li­ty and long life.

It should also be noted that the cor­ro­si­on pro­tec­tion clas­ses are not app­li­ca­ble in the case of very seve­re cor­ro­si­on loads, long pro­tec­tion peri­ods and spe­cial loads. In the case of the­se loads and con­di­ti­ons, the necessa­ry mea­su­res must be deter­mi­ned in each indi­vi­du­al case. The pro­tec­tion peri­od to be achie­ved by the coa­ting sys­tem must alrea­dy be known during plan­ning and design. In gene­ral, the pro­tec­tion peri­od is shor­ter than the expec­ted ser­vice life.

Con­clu­ding remarks:

• The matrix repres­ents a mini­mum level for achie­ving the pro­tec­tion dura­ti­on. Fur­ther wet-che­mi­cal pretre­at­ments such as mul­ti­me­tal-capa­ble nano­cer­a­mics like Bru­gal© (No Rin­se) can incre­a­se the pro­tec­tion dura­ti­on by up to 50%.

• In the case of hot-dip gal­va­ni­zed com­pon­ents, the zinc thic­kness should be mea­su­red in advan­ce as a pro­cess con­trol, as the out­gas­sing beha­vi­or can be stron­gly depen­dent on this. In addi­ti­on, the gal­va­ni­zer should at best indi­ca­te whe­ther pas­siva­ti­on is pre­sent on the gal­va­ni­zed sur­face. In any case, sweeping and out­gas­sing in the fur­nace is recommended.

In the case of sharp-edge­d/la­ser­e­d/­pun­ched com­pon­ents, burrs should always be remo­ved and the edges roun­ded. In addi­ti­on, the sur­face should be free of sca­le and oxi­da­ti­on layers!