The result of studies on the phenomena on metal surface by etectrolysis using the CuSO₄ solution of high conceutration and applying the same method as that in the report 9 are as follows:
(1) A big variation of the “quantities of dissolution and deposition bath valtage” curve appeared at the turrning point of passivation as in the case of the ampere-volt curve.
(2) The dissolved quantities of the anode and the deposited ones on the cathode were almost the same irrespective of concentration of bath and surface area of eledrodes.
(3) A tendency was noticed that the plating degree was less than 100% at low bath voltage and larger than 100% at high bath voltage respectively.
(4) It was another tendency that with an. increase in immersed area of the electrodes the plating degree increased at low bath volteges and decreased at high bath voltages.
(5) The closer tie lay in the relationship between plating degree and bath voltage, as well as between plating dgree and current density.

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It is natural that the roughness of machined surface has much to with capacity, durability, appearance etc. of machinery. With the progress of machining technique, the standardization of surface roughness has become necessary, which many countries in the world have already established.
But it is so troublesome and tedious to measure the surface roughness with surface-roughness-tester, that the so called surface-roughness-scale with which we can find out the roughness of the surface macroscopically or by touching has more and more been called for.
Complying with the requirement, the authers manufactured roughness mother plates of various kinds of machining, and they also studied how far the limits of the roughness of every machining are.

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We discovered suitable alloys which can copy the roughness of other metal surfaces easily, speedily and accurately.
These alloys are composed of less than 20% of lead, less than 10% of tin, between 40 and 65% of bismuth and betmeen 15 and 30% of antimony.
(1) The molten alloy is poured over the surface to be tested after cleaning by benzine trichlorethylen or other organic solvents.
(2) After cooling for solidification the alloy is taken off from the surface to be copied.
(3) Then the roughness of the alloy is measured and recorded by roughness meter.
Conclusion: Since it has low melting point and suitable hardness, the alloy seems to be excellent for copying the roughness of other metal surfaces.

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By using a new powder dispenser, which was constructed to feed powder with constant vetocity by motor drive, the authors tried hot spraying of highpolymers and obtained a film of excellent quality. The surface of the film so formed was smoother and the thickness was more uniform than those obtained with ordinary powder dispenser.

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