Sodium hypophosphite

About: Sodium hypophosphite is a research topic. Over the lifetime, 1695 publications have been published within this topic receiving 15932 citations.

Incorporation of carboxyl groups into xylan for improved absorbency

Abstract: The objective of this research was to investigate green, renewable reaction systems for xylan that introduce crosslinking and carbonyl group for improved performance in water absorption applications. Xylan was modified separately with three different reaction agents, citric acid, succinic anhydride and sodium monochloracetate (SMCA). The xylan was reacted with citric acid in the presence or absence of sodium hypophosphite (SHP) as a catalyst, both in a solution form and in a semi-dry form in an oven. Acid–base titrations, FTIR, TGA, and DSC were used to confirm the composition of the reactant products. Reacted xylan had significantly increased carboxyl content, degree of esterification and degree of substitution with citric acid, succinic anhydride, and sodium monochloracetate. Effective reaction conditions were determined for high yield products. For the xylan reacted with citric acid, the catalyst (SHP) and the use of a semi-dry reaction condition increased the yield significantly. Succinic anhydride and SMCA had high yields. The reaction trends observed were consistent with similar results for starch. Increases in water absorption, saline solution absorption, and decreases in water contact angle for the xylan citrate relative to the xylan indicate that high carboxyl content materials can be generated with xylan and that the resulting materials have enhanced water affinity.

Magnetic recording medium

Abstract: PURPOSE:To obtain a magnetic disk having high resolving power and satisfactory overwriting characteristics by forming magnetic layers whose coercive force is increased toward the center of a disk. CONSTITUTION:An Al disk as a disk substrate is degreased, pickled, zincated, and plated with an Ni-P alloy to 20mum thickness, and it is lapped and immersed in a plating bath. The plating bath is prepd. by adjusting an aqueous soln. contg. CoSO4, NiSO4, sodium hypophosphite, sodium malate, sodium tartrate, (NH4)2SO4 and boric acid to 9.0pH with an NaOH soln. The substrate is rotated at 150r.p.m. in the plating bath at 70 deg.C with a plating jig having 5-200r.p.m. variable speed, and the substrate is plated to obtain a magnetic disk having magnetic films each having 580Angstrom thickness and 750Oe coercive force at the inner part and 750Angstrom thickness and 650Oe coercive force at the outer part by making use of a change in plating speed due to the difference in relative speed between the plating soln. and the substrate to be plated. The change in plating speed is characteristic of electroless magnetic plating. The resulting magnetic disk has high resolving power, satisfactory overwriting characteristics and uniform output characteristics at the inner and outer parts.

Electrochemically Deposited Diffusion Barriers

Abstract: Diffusion barrier properties of electrochemically deposited Ni, Co, and Ni‐Co alloys were examined in the binary system and the Au/Ni/Cu ternary system. Ni and Co were electrodeposited from sulfate or sulfamate (Ni) solutions in the presence of boric acid, at pH 3.30. Electroless Ni and Co deposited either from sulfate or sulfamate solution using sodium hypophosphite or dimethylamine borane as the reducing agent. Electroless gold was deposited from cyanide solutions using potassium borohydride as the reducing agent. The deposits were annealed at 400°C for 14 h in a forming gas atmosphere (10% , 90% ). Auger electron spectroscopy and electron probe analysis were used to assess the extent of interdiffusion as a result of the heat‐treatment. Only electrolessly deposited 1000 A thick Ni, Co, and Ni‐Co alloys have barrier properties for Cu diffusion. For 1000 A thick barriers, annealed for 14 h, the amount of the interdiffused copper into was less than 1 atomic percent. Thicker barriers of , , and are required for the same degree of Cu diffusion. thin films deposited from nickel sulfamate solutions are better diffusion barriers than those deposited under the same experimental conditions, from nickel sulfate solutions. Electrochemically deposited barriers were compared with Ni, Co, and Cr barriers produced by evaporation. The differences between the diffusion barrier properties of deposited from the sulfamate and the sulfate solutions were interpreted in term of microstructural data and grain growth mechanism.