关于镀银层厚度

关于镀银层厚度，我从贾工处了解了一些信息，集合资料，现总结如下：

About the thickness of the silver coating, I get some information from our expert , following is the collection of the information.

电镀性质决定镀层厚度不可能很均匀，边角处、折角处（国际上采用直径为19的球测量直径以外区域，国内用直径20的球测量直径以外区域）、深孔处等只需做到有镀层即可，不可能所有面、所有点都达到5μm以上，只能说主要面最小厚度尽量做到等于或者大于5μm，具体可参考相关电镀标准（国标或者ISO标准）。

Plating’s nature determines that the coating thickness woule not be very uniform. It is acceptable that there are coating at corners(international people measure other area with a ball of diameter 19 while domestic people measure it with a ball of diameter 20) and deep holes. Coating thichness at all faces, points will not be all thicker than 5 μ m. We can only say that we will try our best to achieve that the minimum coating thickness at major surfaces is equal to or greater than 5 μm. And you can refer to related electroplating standard (domestic standard or ISO standard) for details.

1、镀层均匀性：

thickness uniformity

所有电镀层的厚度都不会是均匀的，这是电镀的性质决定的。因为在同一个制件上，电流密度不可能做到均匀。

The coating thickness of all plating will not be uniform, this is determined by the nature of the electroplating. Because in the same product, current density might not be uniform.

不管什么电镀都是厚度不均匀,只是相差的大与小的问题,如挂镀时,每挂最上面和下面的工件肯定会比中间的厚一些,滚镀的有时一些工件滚到一些死角的地方，厚度比那些滚的流畅的工件厚度要薄一些，那单个工件来说，边角部分的厚度比中间部位的厚度要厚，这是肯定的，虽然有些厂里做了工件高区的遮挡，以免电流增大，高区烧焦，也是为了低区的厚度提升，高区厚度降低，来提升整体的厚度均匀，但是还是不可能那么均匀。这所有这些现象都是一个原因，就是电镀产品电镀时的情况就像磁铁一样有一个磁力线原理，边角或尖端的电流线是密集的，中间肯定会比边缘的少的缘故。

No matter what kind of plating it is, the thickness will not be uniform. It is just the problem whether the difference is big or small. such as the huning plating,the top and bottom of every workpiece will be thick than middle,and in rolling plating, sometimes the thickness of some blind angle is thinner than fluent rolling workpiece. It is sure that for the individual workpiece, the thickness of edge is thicker than the middle place.Although some of the factories keep the high place of workpiece be covered to avoid being burned because of the bigger electric current and to improve the uniform of the plating by increasing the thickness of high place and decrease the thickness of low area, the whole thickness is still not so uiform. These phenomena is come from the same reason, that is, just like a magnet, the plating products also have a pricple of magbnetic field lines, the electric current line of corner and sharp corner is intensive, and the coating thickness in the middle must be less than the edge area.

2、电镀工艺缺陷：

Electroplating process defect

工艺允许的缺陷是指由于电镀工艺的限制，在电镀加工过程中出现的不可克服的缺陷，在一定的范围内，不作为不合格的判定依据。工艺允许的缺陷往往是由于镀件结构复杂和电镀工艺技术的限制而难以完全消除的缺陷，比如深孔内可以允许一定孔深内没有镀层，或规定孔口向内的一定距离内有镀层即为合格等。但是工艺允许的缺陷以不损失产品的使用功能为前提，是在不影响产品性能前提下的让步接收。

Allowing process defect means that because of the limitation of plating processes some overcome defects appeare in the process, in a certain range, it would not be the judgement basis as an unqualified product. Allowing process defect is always the result from a complex structure of the plating and the limitation of electroplating process technical which is completely eliminate.For example, in a deep hole, it is allowed that there would be no coating in the certen deepness, or it would regulate that when there is coating from the orifice to the certen distance, it is a qulified product, etc.But the primise of the allowing process defect is that it cannot loss the using function of the product, it would be acceptable when there is no influence to the product.

3、镀层测量 GB12334 等效 ISO 2064

coating measurement GB12334 is equal to ISO 2064

(1) 适用范围本国际标准定义了有关任何基体上的金属和其他非有机覆盖层厚度测量的术语。此外，还规定了一些测量覆盖层最小厚度所要遵循的通则。

Applicable scope, this international standard defines the terms about any substrate of metal and other than organic layer thickness measurement.In addition,it also gives out general rules to measure the minimum thickness of the cover.

(2) 本国际标准采用以下定义①主要表面：工件上已涂覆或待涂覆的部分，对这部分而言，覆盖层对使用性能和/或外观都是至关重要的；并且这部分的覆盖层必须符合所有规定要求。②测量面：主要表面上作单个测量的区域。以下方法的“测量面”的相应定义为：This international standard adopts the following definitions (1) : the major surface: as for the part of workpiece which has been coated or will be coated, it is very important to the use performance and/or appearance. And the cover on this part must comply with all requirements. (2) the measuring surface:the main surface is a single measuring area. Following are the correspondent definitions of “measuring surface” by different ways.

(a)分析法的测量面为退除覆盖层的区域；

Analysis: the measuring surface is the area where the cover is stripped.

(b)阳极溶解法的测量面为电解池封闭圈所包围的区域；

An anodic dissolution: the measuring surface is the area surrounded by electrolysis pool closed circle.

(c)显微镜法的测量面为在规定放大倍数下的视野区域；

Microscopy: the measuring urface is the view area that be enlarged under provide multiple.

(d)无损法的测量面为探头区域或影响读数的区域。

Non-distructive method: the measuring surface is the probe area or the area influences the reading.

③参比面：要求作规定次数的单个测量的表面。

Reference surface: the surface requires specified number of single measurement.④局部厚度：在参比面内规定次数厚度测量的平均值。

Local thickness:the average value by the specified number of measurement of the thickness to the referance surface.

⑤最小局部厚度：在单个工件的主要表面所测得的局部厚度的最小值。