It is observed that the hardness of nickel-phosphorus deposits varies by heat treatment. Nickel electrolytic deposits, nickel-phosphorus electrolytic deposits, nickel-phosporus electroless deposits are obtained from many kinds of baths or various conditions, the hardness is measured and then is heat treated at 200°C, 400°C, and 600°C, for 1hour. 87% nickel-13% phosphorus ingot is treated in the same way.
After heat treatment the hardness is measured and compared, and the relations between the hardness and phosphorus or hydrogen are observed.
1. Before heat treatment the hardness decreases in order of Ni-P electrolytic deposits, Ni-P electroless deposits, Ni-P ingot and Ni electrolytic deposits.
2. After heat treatment the hardness of Ni electrolytic deposits decreases as heat treatment temperature increases.
3. After heat treatment the hardness of Ni-P ingot is almost constant.
4. After heat treating at 400°C for 1 hour the hardness of Ni-P electrolytic deposits and Ni-P electroless deposits show the maximum values. Heat treatment at higher temperature decreases the hardness or even soften the deposits.
5. Contents of phosphorus do not affect directly on hardness, but contents of hydrogen do.

View full abstract

Among various processes hitherto, used in plating nonmetallic surfaces, the chemical plating will be the best. In chemical plating, however, noncatallic surfaces must be activated. The coventional activation was mostly done by immersing in activate solution, such as palladium chloride. The author confirmed that nonmetallic surface could be activated by immersing in stannous chloride solution, But in either palladium chloride or stannous chloride solution, the surface could not completely be activated depending on the immersing condition. The author, therefore, studied the optimum condition of the said solutions on the practical point of view. The results are as follows:
(1) Palladium chloride solution of 0.1g/l, pH value 5.0, temperature 55°C, is found suitable and the optimum condition of stannous chloride soution is to keep its concentration from 20 to 100g/l, and the temperature at less than 35°C. But in the former, short time of immersion is better short, while in the later long time.
(2) The essential points of chemical plating on various nonmetallic surfaces are as follow;
i) Glass and ceramic ware: After chemical echting activation in palladium chloride solution.
ii) Wood: Using the seasoned wood, after saturated with white wax, activation in stannous chloride solution, plating in alkaline plating bath.
iii) Organic synthetic materials: After polishing with abrasive, activation in stannous chloride bath first, and then in palladium chloride solution, after plating, immerse in boiling water to dry.
iv) Carbon: After cleaning and removing the carbon powders activation of the surface.

View full abstract

Contact angle of an oil droplet placed on a horizontal metal surface is used one of the characteristic values of such clock oil, lubricant fraction of mineral oil, rust preventive oil, etc. This value shows the adhesion wetting of test oil against metal surface. And it is necessary to standardize the dropping method, the drop volume and the time after deposit on toget its reproducibility. It is better to use a small wire immersed in test oil, draw out and trickle the drop let on the test surface, for better reproducibility. The volume of drop is about 0.004ml. The contact angle of oil is measured after 3 minutes by means of a goniometer eyepiece constructed by the author. When the metal surface is absorbed and coated by oleophobic molecular layers of such stearic acid or its derivatives etc., an oil drop on it shows a large contact angle of 40-50°. But the contact angle of oil drop for bare metal surface is less than 10°.
The difference between new polished surface by emery paper and its aged surface about 24 hours can be distinguished by the contact angle of distilled water drop, but it can not be distinguished by that of oil drop. Surface tention of mineral oil is scarcely changed by addition of 4-5% of the polar type rust preventive additives.

View full abstract