Determination of Oxygen in Metallic Manganese by Argon-Carrier Fusion Method

Determination of oxygen in metallic manganese, which is considered to be difficult by the conventional vacuum fusion method, was attempted by the argon-carrier fusion method. The gettering effect of manganese was found to be inhibited by useing a fresh bath, containing tin 15～20 times the amount of sample, for each run and by carrying out the analysis at 1650±30℃. Analyses of several kinds of metallic manganese sample under these conditions gave well-reproducible results. Recovery of oxygen was determined to be 95～110% by the addition of a definite amount of manganese oxide to these samples, showing that the gettering effect of manganese is inhibited completely

Blue light-emitting diode based on ZnO

A near-band-edge bluish electroluminescence (EL) band centered at around 440 nm was observed from ZnO p-i-n homojunction diodes through a semi-transparent electrode deposited on the p-type ZnO top layer. The EL peak energy coincided with the photoluminescence peak energy of an equivalent p-type ZnO layer, indicating that the electron injection from the n-type layer to the p-type layer dominates the current, giving rise to the radiative recombination in the p-type layer. The imbalance in charge injection is considered to originate from the lower majority carrier concentration in the p-type layer, which is one or two orders of magnitude lower than that in the n-type one. The current-voltage characteristics showed the presence of series resistance of several hundreds ohms, corresponding to the current spread resistance within the bottom n-type ZnO. The employment of conducting ZnO substrates may solve the latter problem.Comment: 13 pages, 4 figures. Jpn. J. Appl. Phys. in pres

Studies on Gas Analysis in Metallic Titanium

Determination of hydrogen, oxygen and nitrogen in metallic titanium was studied by the vacuum fusion method and the chlorination method. By the vacuum fusion method, hydrogen and oxygen were completely extracted and could be determined at 1850～1900℃ by using iron bath, but nitrogen was not extracted. By the chlorination method, oxygen could be determined at 300℃ in a stream of mixed gases of chlorine at 5ml/min and nitrogen at 20～30ml/min. These results agreed well with those by the vacuum fusion method

Determination of Oxygen in Metals by Argon Carrier-Fusion Coulometric Titration Method

The automatic coulometric titration apparatus was tentatively used for the determination of oxygen in metals by the argon carrier-fusion method. The whole procedure was very rapid to complete the analysis and the blank value was very small with little variation. Each analysis of various kinds of iron and steel sample could be made within 3 to 5 minutes with high precision and accuracy. The determination of oxygen in ferromanganese, titanium, and Zircalloy was also examined and a statisfactory result was obtained by the use of a tin bath for ferromanganese, and an iron-tin bath for titanium and Zircalloy. Oxygen in ferrochromium was determined at high analytical temperatures

Determination of Oxygen in Cast Iron

Recently, the determination of oxygen in cast iron has been required and it is important to determine not only the total amount of oxygen but also the oxygen in each oxide. The non-metallic inclusion method is usually used for determing each oxide in cast iron, which, however, is tedious and not reliable. Hence, the fractional vacuum fusion method was studied, and it was found that by using a tin-bath, FeO could be extracted at 1050℃, MnO at 1150℃, SiO_2 at 1450℃ and Al_2O_3 at 1750℃ by this simple method. For comparison, samples of the same cast iron were also analyzed by the hot nitric acid method, the chlorine method and the electrolytic method, and satisfactory results were obtained by the fractional vacuum fusion method in comparison with the case of the non-metallic inclusion method