燒結 Nd2Fe14B 易被腐蝕,尤其是磁體邊沿,腐蝕會導致產品嚴重變質, 包括將磁鐵粉碎成小磁性微粒的粉末, 或表面層剝落。因此,添加保護塗層來防止接觸大氣層來解決這缺陷。鍍鎳、鍍鋅、雙層銅鎳電鍍或環氧電泳是常見的電鍍方法。
Sintered Nd2Fe14B tends to be vulnerable to corrosion, especially along grain boundaries of a sintered magnet. This type of corrosion can cause serious deterioration, including crumbling of a magnet into a powder of small magnetic particles, or spalling of a surface layer. This vulnerability is addressed in many commercial products by adding a protective coating to prevent exposure to the atmosphere. Nickel plating, zinc plating, epoxy plating or two-layered copper-nickel plating are the standard methods, although plating with other metals, or polymer and lacquer protective coatings are also in use.
電鍍性能 Properties of Electroplating | |||||
塗層種類 Types of Coating | 塗層厚度 Thickness (μm) | 顏色 Colour | 工作温度Working Temperature | PCT | SST |
鋅 Zn | 5-15 | 白色 White | ≤ 160℃ | >15Hr | >24Hr |
彩鋅 Colourized Zn | 5-15 | 多彩Multicolour | ≤ 160℃ | >24Hr | >48Hr |
鎳 Ni | 10-20 | 銀色 Silver | ≤ 200℃ | >48Hr | >100Hr |
雙層鎳 Double Ni | 10-20 | 銀色 Silver | ≤ 200℃ | >48Hr | >100Hr |
鎳銅鎳 NiCuNi | 12-25 | 銀色 Silver | ≤ 200℃ | >48Hr | >100Hr |
化學鎳 Electroless Ni | 10-20 | 銀色 Silver | ≤ 200℃ | >48Hr | >100Hr |
環氧 Epoxy | 15-30 | 黑色 Black/ 灰色 Gray | ≤ 160℃ | >96Hr | >500Hr |