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A study has been made on the decarburization of electrical steels containing various amounts of Si in wet hydrogen atmosphere of dew points from 20℃ to 50℃ at temperatures from 700℃ to 950℃. For electrical steels with low Si content (below about 0.5%), the decarburization degree at high temperature (above about 850℃) was more influenced by the change of the diffusion coefficient which was caused by the phase transformation than by the oxide scale formed during annealing. For electrical steels with high Si content (above about 2%), the decarburization degree was mainly influenced by the oxide scale formed doting annealing. For electrical steels with medium Si content (about 0.9-1.5%), the decarburization degree at high temperatures (above about 850℃) was mainly influenced by the increase of diffusion coefficient due to temperature increase and the oxide scale formed during annealing.

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A study has been made on the change of hardness, lattice parameter and thermal stability in Al-X (X＝Ti, Zr, V) alloys which were produced by the Atomization-Splat Quenching method. Analysis of diffraction pattern was performed by computer for aging mechanism. In Al-Zr alloy, aging peak is obtained at 400℃ for 1 hour in the Vickers hardness test. Coherent metastable phases are detected by the TEM analysis during aging treatment. For Al-Ti alloy, it is found that the metastable structure is tetragonal (a＝12.4-12.6 A, c＝13.7-14.3A). When the alloys are heat-treated at 400℃ for 100 hours, the morphologies of precipitates are different each other.

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A study on the fracture toughness of WC-Co using alloys is made single-edge notched beam specimens pre-cracked by electron-discharge machining. The microstructural parameters are determined on the electron micrographs by linear analysis. The relations between K_(IC) and the microstructural parameters show that K_(IC) tends to increase with increased binder volume fraction and cobalt mean free path and tends to decrease with increases in WC contiguity, but cannot be related only to one microstructural parameter. A structure model is sugested to estimate the fracture path in WC-Co alloys and the critical strain energy release rate is evaluated from this fracture model.

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Quaternary systems Cu-Sb-Ni(Co, Fe)-S and ternary system Cu-Sn-S with Au or Pt were studied at 1200℃ for Au and Pt distribution between matte and speiss. The results of this study are as following: 1) Au or Pt is soluble in speiss, because the Cu content except Cu included as Cu₂S in speiss is higher than that in matte. 2) Distribution coefficients of Au and Pt(K_(Au) and K_(Pt)) in the quaternary systems have similar trends, and the ratio of K_(Au) : K_(Pt) is about 10:1. 3) K_(Au) and K_(Pt) in Cu-Sb-S system are decreased with the addition of Ni, Co and Fe. 4) The effect of Ni on Au solubility in speiss is not same as that of Co or Fe, because Ni forms solid solution with Au in all composition range. 5) K_(Au) or K_(Pt) in Cu-Sn-S system is not nearly changed with the decreasing of Cu content in speiss. And the value of K_(Au) is less than 10 times of K_(Pt).

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The thermal stability for the amorphous (Fe_(l-x)Co_x)_(80)B_(20) alloys has been studied systematically through DTA, X-ray diffraction pattern and the electrical resistance change response to temperature and time variations. The results obtained are as follows; 1) The crystallization temperature of amorphous (Fe_(l-x)Co_x)_(80)B_(20) alloy is independent of the concentration of Co and it is about 710˚K. 2) The crystallization process of amorphous (Fe_(l-x)Co_x)_(80)B_(20) alloy occurs in two steps; In the composition range of 0.1≤x≤0.5, amorphous (Fe_(l-x)Co_x)_(80)B_(20)→α phase (Fe, Co; bcc)＋Fe₃B(bct) →α phase (Fe, Co; bcc)＋Fe₂B(fct)＋Co₂B(fct), and in the composition of x = 0.6 amorphous (Fe_(l-x)Co_x)_(80)B_(20)→α phase (Fe, Co; bcc) ＋Fe₃B(bct)＋Co₃B(fct) →αphase (Fe, Co; bcc)＋Fe₂B(fct)＋Co₂B(fct), and in the composition of x = 0.7 amorphous (Fe_(l-x)Co_x)_(80)B_(20)→αphase (Fe, Co; bcc) ＋Co₃B(fco)→αphase (Fe, Co; bcc)＋Fe₂B(fct)＋Co₂B(fct) 3) The crystallization of amorphous (Fe_(l-x)Co_x)_(80)B_(20) is the diffusion-controlled nucleation and growth process, and the crystallization activation energy of amorphous (Fe_(l-x)Co_x)_(80)B_(20) alloy is independent of the composition of Co and it is about 70㎉/mole.

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This study is made, considering that cadmium has various problems as an impurity in the electrowinning process of zinc, (1) to elucidate the behavior of zinc-cadmium electrodeposition depending upon the change of several fundamental factors of the process, (2) to observe the procedure of zinc-cadmium alloy electrodeposition with reference to the polarization curves, (3) to find out the mechanism of the formation of metallic hydroxide according to high pH value in the vicinity of the cathode, and finally (4) to make clear the mechanism of zinc-cadmium alloy deposition by measurement film resistance.

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