江戸時代に製造された火縄銃の非金属介在物の組成と構造

抄録

  The composition and microstructure of nonmetallic inclusions of a Japanese matchlock gun, called Hinawa-ju in Japanese, fabricated in the Edo period have been investigated. The purpose of this work is to study the composition and microstructure of nonmetallic inclusions of the barrel and to obtain modern materials-science data of the raw materials of the Japanese matchlock gun. Test pieces are cut from the center and the male screw of the barrel. Nonmetallic inclusions of the barrel are observed using an optical microscope and scanning electron microscope (SEM). The small-area concentration of a nonmetallic inclusion is obtained by electron dispersive X-ray analysis (EDS). The electron backscattering pattern (EBSP) is analyzed using an ultrahigh-resolution scanning electron microscope. Fe, Si, Al, Ca, K, Mg, P, Na and Ti are detected from nonmetallic inclusions of the center of the barrel. As Ti is detected from many parts of the nonmetallic inclusions, iron sand is inferred to have been used as the raw iron material of the barrel. Nonmetallic inclusions of the center of the barrel are classified into two groups. One is a plural phase and is consisted of FeO (wustite), Fe-Si-O grains, multi-element grains and glass-rich matrix oxide. The other type is a single phase of aluminum silicate glass. Fe, Si, Al, Ti, Ca, Mg, K, Na, P, Mn and S are detected from nonmetallic inclusions of the male screw of the barrel. As Ti is detected from many parts of the nonmetallic inclusions, iron sand is again thought to have been used as the raw iron material of the male screw. Nonmetallic inclusions of the male screw are of the plural phase and consist of Fe-Ti-O grains, aluminum silicate oxide and aluminum silicate glass matrix.