近年由於可攜式電子產品盛行，使得電子零件需不斷往薄形化、小型化、表面黏著化發展，使市場上對晶片型負溫度係數(NTC)熱敏電阻之需求日亦殷切。在製作NTC熱敏電阻之端面電極時，需在元件兩端沾附上40～50μm厚度之銀電極，經600℃～650℃燒成後，先後電鍍上2～4μm厚之Ni層及5～10μm之Sn或Sn-Pb層，以使元件具有較佳良之銲錫性。但因熱敏電阻材料為一半導性陶瓷，在電鍍過程會發生電鍍層擴散之現象。
　　本研究利用磷酸鹽化成處理，藉由磷酸根與(Co,Mn)(Mn,Co)2O4反應，在負溫度係數熱敏電阻元件表面製作具絕緣性、抗電鍍藥水侵蝕之磷酸錳保護皮膜，探討(1)化成處理過程中，催化劑種類及不同濃度對化成處理之影響。(2)改變化成處理溫度及時間，以探討對磷酸錳皮膜之結構及材料性質之影響。
結果發現以磷酸錳溶液為化成處理液，添加Zn+2離子為催化劑，經90℃，1小時之化成處理可在NTC熱敏電阻之表面生成完整之MnPO4‧H2O皮膜，而皮膜之生成機構為NTC熱敏電阻組成中之富錳區域首先溶解，待磷酸錳溶液中之Mn+3離子與溶液中PO43-反應，在熱敏電阻組成中富鎳之區域析出，形成磷酸錳皮膜。

　　Owing to the prevalence of portable electronic device in recent years, the development of electronic components trends towards thinner, smaller and much surface adherent. It turns out to ferment the demand for NTC thermistor. When producing NTC termination electrodes, in order to enhance the solder property, we have to 1) attach silver electrodes to components about 40~50μm thickness, 2) co-fire in 600℃～650℃, and finally 3)coat Ni-layer with 2～4μm thickness and Sn- or Sn-Pb layer with 5～10μm thickness. However, NTC thermistor is of semiconducting ceramics, resulting in the diffusion phenomenon in electroplate layer during electroplating.
　　In this research, on the surface of NTC thermistor, we employ phosphate ion conversion treatment, by the reaction of phosphate ion and (Co,Mn)(Mn,Co)2O4, to construct manganese phosphating protection layer, which is resistance and defending for the corrosion due to electroplate liquid. Moreover, we also investigate 1) the effect with respect to the variation of sorts of accelerator and the variation of accelerator concentration, and 2) the influence on the surface structure and material property of manganese phosphating layer by changing temperature and time of conversion treatment.
In consequence, on the surface of NTC thermistor, ideal MnPO4‧H2O layer can be constructed by 1) utilizing the solution of manganese phosphating as the conversion treatment liquid in which Zn+2 ions are added as accelerator, and by 2) 90℃ and 1 hour conversion treatment. The mechanism of layer producing is in that 1) first the Mn-rich region in the composition of NTC thermistor is dissolved, 2) Mn+3 ions from manganese phosphating solution thus react with PO43- ions within the solutions, and 3) finally the Ni-rich region in the composition of NTC thermistor precipitates MnPO4‧H2O, forming the manganese phosphating layer.

1.http://en.wikipedia.org/wiki/Parkerizing
2.W. S. Lee,W. T. Chen,T. Yang,Y. C. Lee,C. Y. Su,S. P. Lin,C. L. Hu, Journal of the European Ceramic Society ,26 (2006) 3279-3285.
3.C. Clinton,T. R. Spalding, A. M. Connell, J. Barrett,and J. F. Rohan, “Phosphate coating for varistor and method”,U.S. Patent No. 6,214,685.
4.P. Ravindranathan, “Zinc phosphate coating for varistor and method”, E.P.Patent No. 0 806 780 A1.
5.K. Shiraishi,T. Inoue,R. Sasaki,K. Noi,and H. Tokunaga, “Zinc oxide varistor and method of manufacturing same”,U.S. Patent（2003）0043013 A1.
6.H. Tokunaga,M. Higashitani,and Y. Wakahata,“Method for manufacturing varistor”,U.S. Patent No. 6,260,258 B1.
7.H. Tokunaga,M. Higashitani,and Y. Wakahata,“Method for manufacturing varistor”,U.S. Patent No. 6,262,258.
8.D.B.Freeman,“Phosphating and Metal Pre-treatment,A Guide to Modern Processes and ractice”,Woodhead-Faulkner,Cambridge,1986.
9.Y. C. Yu，N. Li，H. L. Hu，J. S. Zhang，Z. H. Tu, Research Development of Non-chromate and Tri-chromium Passivation , Surface Technology,34（2005）6-9.
10.賴文啟,鎂鋁合金錫酸鹽皮膜化成處理之研究,2003。
11.T.S.N. Sankara Narayanan,Rev. Adv. Mater. Sci. ,9 (2005) 130-177.
12.A.L. Rudd, C.B. Breslin and F. Mansfeld, The Corrosion Protection Afforded by Rare Earth Conversion Coatings Applied to Magnesium , Corrosion Science, pp.275~288，2000。
13.正文書局編譯委員會譯編,表面處理法,正文書局。
14.陳清松,塗料與塗裝技術,11(1988)58-60。
15.王詔明, 析鍍條件及熱處理對磷酸錳鍍層微結構及電化學性能影響之研究,2007。
16.Kevin Ogle,Michael Wolpers,“Phosphating conversion coatings”,in ASM Handbook vol.13A
17.MIL-P-16232F,“Phosphate coating,Heavy,Manganese or Zinc”,1978