| 摘要 |
<p>Metallic surfaces, esp. iron and steel, are chemically treated to produce coatings which support lubricants, e.g. mineral, animal and vegetable oils and greases and soap, for e.g. wire drawing, stamping, deep drawing and metal spinning, by immersing the metal to form a phosphate layer, then withdrawing the part from the bath and allowing the soln. to dry without prior rinsing, thus leaving a second layer contg. inorg. salts superimposed on the first phosphate layer. The soln. consists of 5-200 g/l alkaline or ammonium phosphates, 0-20 g/l oxidising agents, 0-10 g/l reducing agents, 0-20 g/l activators, 0-300 g/l inorg. cpds. for the reinforcing layer, and surface active agents at pH 3-6, and temp. >50, pref. >80 degrees C. The oxidising agents may be nitrates, chlorates or bromates, or org. nitro cpds. The reducing agents include hydroxylamine, activators used include molybdates, vanadates, nickel, cobalt or copper salts, simple or complex fluorides. The addns. for the sec. inorganic layer may include alkaline, chlorides, sulphates, nitrates, fluoborates and/or fluosilicates and insol. inorg. suspensions such as bentonites, graphite, pyrophosphates of iron, zinc, tin or magnesium, mica, etc. The use of these coatings extends the life of the tools and allows a faster and easier prodn.</p> |
