Abstract: A catalyst for removing nitrogen oxides from an exhaust gas comprises a composite oxide or mixture of niobic acid or niobium oxide with iron oxide or hydrated iron oxide. The catalyst contains atoms of niobium and atoms of iron in a ratio Nb/Fe not exceeding about 1. The catalyst is useful for converting nitrogen oxides in an exhaust gas to nitrogen gas by contacting the exhaust gas with the catalyst in the presence of a reducing gas, such as ammonia. The catalyst can be prepared by impregnation or coprecipitation.

Abstract: A solid state catalyst consists essentially of hydrated niobium oxide containing a phosphoric acid on its surface in an amount sufficient to increase surface acidity, to inhibit crystallization of the niobium oxide and to retard loss in catalytic activity following exposure to high temperature. The catalyst can be prepared by treating hydrated niobium oxide (Nb.sub.2 O.sub.5.xH.sub.2 O) or an anhydride thereof with a phosphoric acid. The catalyst is useful in the hydration of ethylene to form ethanol.

Abstract: A surface treated steel materials coated with manganese having a film of MmOOH (manganic hydroxide) formed thereon, which show excellent corrosion resistance, workability and weldability. The surface treated steel materials may be further coated with zinc as a base coating underlying the manganese coating or further coated with a coating of at least one selected from the group consisting of P, B, Si, Cu, Mn, Cr, Ni, Co, Fe, Zn, Al, Ca, Mg, Ti, Pb, Sn, inorganic carbon and their compounds and still further coated with an organic coating. The film of MmOOH (manganic hydroxide) is formed by a treatment in an aqueous solution containing Cr.sup.6+.

Abstract: Manganese coated steel materials having a compact film of hydrated manganese oxide formed on the manganese coating by heating and drying. Manganese coated steel materials of the present invention show very excellent corrosion resistance in ordinary corrosive environments as well as special corrosive environments such as marine environments and young plant cultivation in mountaineous forests. For further improvement of corrosion resistance, organic coating and metal coatings are applied.

Abstract: An austenitic heat-resistant steel which forms an oxide film mainly composed of Al.sub.2 O.sub.3 in a high-temperature oxidizing atmosphere, consisting essentially of not more than 0.2% of C, not more than 1.0% of Si, not more than 2.0% of Mn, 12 to 37% of Ni, 9 to 25% of Cr, more than 4.5 but not more than 6% of Al, and at least one member selected from the group consisting of Ti, Nb and Zr in a total amount of not more than 0.8%, with the balance being Fe; the .delta.-ferrite value of this steel, calculated from the formula set forth below, is from 0 to 7.9; this steel is removed of an internal oxide layer which has been formed just below the steel surface during hot working. ##EQU1## where Wi and Mi represent, respectively, the percent by weight and the atomic weight of Ti, Nb and Zr, and when the term ##EQU2## is negative this term is regarded as zero. This steel composition may contain one or more rare earth elements such as Y, Ce and La in a total amount of not more than 0.08%.

Abstract: A stainless steel pipe having a surface layer with excellent resistance against vanadium pentoxide attack experienced upon boiler heating tubes for power generation, corrosion by sulfates, corrosion by chlorides experienced upon boiler heating tubes for various burning furnace and high-temperature gas corrosion experienced upon tubes for heating furnaces in the chemical industry, and also relates to methods for forming the surface layer.

Abstract: A ferritic stainless steel having high toughness both in the weld zone and the base metal comprising:C .ltoreq. 0.05%si .ltoreq. 0.7%1.0 < Mn < 2.5%Cr = 10% - 19% (exclusive)Ti = 5 .times. C% - 0.5%n .ltoreq. 0.03%al .ltoreq. 0.5%Balance: Fe and unavoidable impurities.

Abstract: Surface treatment of weather-resistant steel by applying a liquid composition comprising 5 to 50% of Fe.sub.3 O.sub.4 + Fe.sub.2 O.sub.3, 0.01 to 5% of phosphoric acid, 0.01 to 10% of at least one selected from the consisting of Pb, Ni, Cu, P, Zn, Cr and their compounds, 3 to 30% of butyral resin, the balance being solvent by spraying or brushing. The surface treatment is effective for preventing the occurence of the initial rust formation of the steel and promoting a stable and dense protective rust against subsequent corrosion of the steel.