The anode made of 1.3cm×1.4cm titanium plate, the impurities of which are less than 0.07% Fe, less than 0.02% Si, and less than 0.2% Ni (the balance is Ti), is immersed in the electrolyte of HCl, HNO₃ or H₂SO₄, at the distance of 3cm from the cathode of platinum plate.
Photographs of the anodic polarization potential curves by a pulse-polarizer were taken, and the areas between the curves and the horizontal line denoting the natural electrode potential are measured (volt-sec).
The corrosion tendency is investigated on the assumption that the tendency is proportional to the reciprocal of the dimension of the area above mentioned.
The result: In HCl electrolyte, the corrosion increases with an increase in the concentration of the electrolyte, in HNO₃ electrolyte, it is almost unchanged with a change in the concentration: and in H₂SO₄ electrolyte, it reaches its maximum at the concentration of 40% or 75%.

View full abstract

We applied hot-dip aluminium coating under the following conditions on the mild steel wire (rimmed steel containing 0.07%C) and the steel wire (containing 0.5%C) each cold drawn to 0.5mm diameter and examined the mechanical properties of those aluminium coated wires.
The fluxes utilized in this coating process are ammonium chloride vapour and staurated zinc chroride and amonium chroride (ZnCl₂: NH₄Cl=87:13 by weight) aqueous solution held at 80°C. Thee molten bath of aluminium is maintained at 680, 700, 720 and 750°C, and immersion time in it is 1, 2 and 5 seconds at every temperature.
When a cold drawn steel wire having 162kg/mm² tensile strength and 1% elongation (100mm G. L.) is aluminium coated by hot-dip process, the tensile strength decreases to 100, 90 and 87kg/mm² at 680, 700 and 730°C of the metal bath temperature respectively, and the elongation increases 5-6%. Accordingly, it is difficult to obtain an aluminium coated high strength steel wire by the hot-dip process.
When a cold drawn mild steel wire having 95kg/mm² tensile strength and 1% elongation is coated by the same process, the tensile strength decreases to around 50kg/mm², while the hot-dip galvanized same wire has about 80kg/mm² tensile strength. But such a hot-dip aluminium coated wire has a little higher tensile strength than that of the same wire only passed through a molten lead bath under the same condition, because the hard and brittle alloy layer is formed on the surface of wire by the hot-dip aluminium coating process. The elongation increases to 10% by coating but this value is only a half of that of the wire passed through the molten lead bath at the same temperature and same speed.
It is desirable to maintain the molten metal bath temperature as low, and the immersion time as short as possible.

View full abstract

This report deals with the relationship betwean the amounts of anodic dissolution and cathodic deposition in copper plating.
A series of experiments is done under the following conditions:
Bath Concentration……10% of CuSO₄·5H₂O
Bath Temperature……20±0, 5°C
Plating Time……20min,
Size of Electrode……5mm×50mm or 10mm×50mm
The result:
1. In the plating between 2 and 3 volts, the amount of anodic dissolution is the same as that of cathodic deposition. But, the plating below 2V, the amount of anodic dissolution is greater than the cathodic depositon, and above 3V, the former is smaller than the latter.
2. The grades of the curves of the amount of anodic dissolution against voltage and that of cathodic deposition against voltage are similar to that of ampere-voltage curve. The three curves change remarkably when the anode takes a passive state.
3. Assuming that a plating degree is expressed by“the amount of cathodic deposition/the amount of anodic dissolution×100”(%), it becomes nearly 100% between 2 and 3V. However, it becomes 100% after long time plating only when the voltage is lower than 2V.

View full abstract