Colour and structural changes of Metallic Sulfide and Selenide : HgS, HgSe, ZnS, CdS, CdSe were investigated by grinding in an agate mortal. These have two crystal forms (zinc blende, wurtzite) in normal conditions. Mechanochemical phenomena of the mixtures by grinding have been investigated by X-ray diffraction analysis and Spectrophotometer. HgS (cub.) was transformed easily into wurtzite form by grinding for 10 hr, but HgS (hex.) was not transformed into zinc blende form on further grinding. When two components : HgS (cub.) -ZnS (cub.), CdS (cub.) -ZnS (cub.), CdS (hex.) -CdSe (hex.) were mixed and ground for several hours in air, the clear structural change into continuous solid solution (zinc blende form) of the substitutional type were shown. Continuous solid solution of the mixtures and obedience to Vegard's law were recognized by X-ray diffraction analysis. Whereas, when two components : HgS (cub.) -HgSe (cub.), CdS (hex.) -HgS (hex.) were mixed and ground, the crystal forms of the subsequent transformation depend on the mixing ratios of components. The hue of solid solution (zinc blende form) obtained with the two components; CdS (hex.) -HgS (hex.), (CdS/HgS : 8/1, mol ratio) was yellowish red. The characteristic peaks of X-ray diffraction of the solid solution after 50 hr grinding agreed with that of CdS (cub.).
Infrared spectra of calcium sulfite tetrahydrate crystals (metastable phase) obtained from the Ca (OH) 2-S02 reaction systems (0°C) by adding Cu (II) ion, Zn (II) ion, or Ni (II) ion (5.0×10-3M) were measured. The infrared spectra of calcium sulfite hemihydrate crystals (stable phase) indicated a relatively small peak of O-H stretching of the crystal water at 3,380 cm-1, while spectra of the tetrahydrate crystals had a very large peak (3,000-3,900 cm-1) in the 0-H stretching region. The infrared spectra of the hemihydrate crystals indicated a peak of S-O (S=0) of the sulfite ions only at 930 cm-1, while spectra of the tetrahydrate crystals showed the presence of two distinct groups of bands (930 and 980 cm-1) in the S-O (S=O) stretching region. These results suggested the differences of bonding around S-atoms and 0-atoms in the tetrahydrate crystal and in the hemihydrate crystal. The thermostability of the tetrahydrate crystals were examined by DTA, TG and DSC. The order of the magnitude of the function of metal ions to stabilize the tetrahydrate crystal was as follows; Cu (II) > Zn (II) >Ni (II). It was revealed that the change of tetrahydrate to hemihydrate gave the heat absorption of about 17 kJ/mol almost irrespective of kinds of metal ion added to the reaction system.
For applications of polyvinyl chloride resin coated galvanized steel sheet to outdoor building materials, the coated film sometimes peels off depending on the use conditions. Therefore, a need has existed for developing method for predicting the life time of the coated steel sheet for peeling off. This paper examines the service life for peeling off of the coating film of polyvinyl chloride resin coated galvanized steel sheet, by measuring the amount of the chlorine in the surface layer of polyvinyl chloride resin coating film with fluorescent X-rays to obtain the degree of the decomposition of polyvinyl chloride resin. The results obtained are as follows; (1) The amount of the chlorine in polyvinyl chloride resin can precisely be measured with the intensity ratio of ClKα/TiKα of fluorescent X-rays. (2) There is a correlationship between peeling off and retention rate of ClKα/TiKα in outdoor weathering test. When the retention rate gets under 70%, the condition for the peeling off of coating film suffices. (3) The successive change of ClKα/TiKα retention rate in outdoor weathering test is affected by the film thickness of polyvinyl chloride resin, and the amounts of titanium dioxide pigment and iron oxide pigment. (4) The service life for peeling off of the coating film of polyvinyl chloride resin coated galvanized steel sheet can be predicted in a short period by obtaining the successive change of the retention rate of ClKα/TiKα in accelerated weathering test.