Abstract: A metal joined body has an iron base body and an aluminum base body that are joined together via a joint layer. The joint layer has a first layer composed of a first intermetallic compound formed on the iron base body side and a second layer composed of a second intermetallic compound formed on the aluminum base body side. The first layer has one or more first protrusions that merge integrally into the iron base body and extend in a pile shape into the first intermetallic compound. The second layer may have one or more second protrusions that are composed of a second intermetallic compound and extend in a columnar shape into the aluminum base body. The first intermetallic compound may contain Al5Fe2, and the second intermetallic compound may contain Al3Fe. The total thickness of the first layer and the second layer is, for example, 2 to 15 ?m.

Abstract: A metal-resin composite material including an aluminum substrate having an aluminum oxide coating and a resin bonded to the aluminum substrate through the aluminum oxide coating, wherein the aluminum oxide coating has a porous surface layer in which columns with an average height of 10 to 100 nm are arranged in a dispersed state, an average value of sums of cross-sectional areas of the columns in randomly sampled 400 nm square visual fields of the porous surface layer is 8000 to 128000 nm2, an average value of sums of circumferential lengths of cross-sections of the columns in randomly sampled 400 nm square visual fields of the porous surface layer is 1000 to 27000 nm, and an average value of numbers of the columns in randomly sampled 400 nm square visual fields of the porous surface layer is 10 to 430.

Abstract: A metal-resin composite material including an aluminum substrate having an aluminum oxide coating and a resin bonded to the aluminum substrate through the aluminum oxide coating, wherein the aluminum oxide coating has a porous surface layer in which columns with an average height of 10 to 100 nm are arranged in a dispersed state, an average value of sums of cross-sectional areas of the columns in randomly sampled 400 nm square visual fields of the porous surface layer is 8000 to 128000 nm2, an average value of sums of circumferential lengths of cross-sections of the columns in randomly sampled 400 nm square visual fields of the porous surface layer is 1000 to 27000 nm, and an average value of numbers of the columns in randomly sampled 400 nm square visual fields of the porous surface layer is 10 to 430.

Abstract: A method for evaluating a solder joint portion by means of which a part and a substrate are joined to each other includes a preparation process for preparing the substrate including the solder joint portion, a thermal shock process for applying thermal shock to the solder joint portion multiple times, and an evaluation process for obtaining a change of a crystal grain size in the solder joint portion caused by the application of the thermal shock so as to evaluate a lifespan of the solder joint portion based on the change of the crystal grain size obtained.

Abstract: A method for evaluating a solder joint portion by means of which a part and a substrate are joined to each other includes a preparation process for preparing the substrate including the solder joint portion, a thermal shock process for applying thermal shock to the solder joint portion multiple times, and an evaluation process for obtaining a change of a crystal grain size in the solder joint portion caused by the application of the thermal shock so as to evaluate a lifespan of the solder joint portion based on the change of the crystal grain size obtained.