China
Africa
Explore chapters and articles related to this topic
Phosphorous-Based FRs
Published in Asim Kumar Roy Choudhury, Flame Retardants for Textile Materials, 2020
RPO(OH)2+NaOH→H2O+RPO(OH)(ONa)(monosodiumphosphonate)RPO(OH)(ONa)+NaOH→H2O+RPO(ONa)2(disodiumphosphonate Phosphonate esters are the result of condensation of phosphonic acids with alcohols. Phosphinates or hypophosphites are a class of phosphorus compounds that are conceptually based on the structure of hypophosphorous acid. IUPAC prefers the term phosphinate in all cases; however in practice, hypophosphite is usually used to describe inorganic species (e.g., sodium hypophosphite), while phosphinate typically refers to organophosphorus species.
Study on the degreasing and etching operations in the pre-treatment of ABS dielectric aimed at obtaining quality chemically deposited nickel-phosphorus coatings
Published in Transactions of the IMF, 2019
V. Chakarova, M. Georgieva, Ek. Dobreva, M. Petrova
Chemical nickel-plating is an autocatalytic reduction of nickel ions at the boundary surface of a heterogeneous system. The most commonly used chemical nickel-plating solutions contain two basic components: nickel salt and a reducing agent as sodium hypophosphite, boro-hydride, boro-nitrogen containing compounds, hydrazine and others. In practice, the most widespread solutions are those containing sodium hypophosphite as a reducing agent. They also contain ligands of the nickel ion, buffering substances, stabilisers, accelerators, brighteners and other substances. The product of the chemical nickel-plating process using hypophosphite reducing agent is not a pure nickel coating but it always contains phosphorus which is incorporated into the coating as an intermetallic compound. The amount of phosphorus in the coating varies depending on the conditions of the process.13,14
Modelling of surfactants and chemistry for electroless Ni-P plating
Published in Surface Engineering, 2018
Amir Farzaneh, Maryam Ehteshamzadeh, Andrew J. Cobley
Sodium hypophosphite is used as a reducing agent in the EN-P plating. There are many studies concerning the effect of hypophosphite concentration and pH on EN-P deposition rate [14]. It has been reported that the effective molar ratio of Ni+/H2PO2− should be fixed within a limited range of 0.25–0.60, but the suitable range can be 0.30–0.45, in order to achieve optimum Ni-P coating properties [1,14,20]. The nickel concentration, of an acidic type EN-P solution (pH = 4–6), is normally between 4.5 and 11 g L−1 (0.08–0.19 M) [14]. By using this nickel concentration range and the preferred molar ratio of Ni+/H2PO2−, the sodium hypophosphite concentration range obtained is typically between 0.18 and 0.27 M.
Effect of heat treatment on microstructure and tribology behaviour of electroless Ni-P/BN(h) composite coating
Published in Transactions of the IMF, 2020
Shuai Li, Shuai Pu, Zongying You, Caiyuan Sun, Songxia Li, Jin Zhang
In the plating bath, nickel sulphate was used as the source of nickel, sodium hypophosphite as the reducing agent. Trisodium citrate dihydrate, sodium acetate and sulphocarbamide were used as complexing agent, buffering agent and stabiliser, respectively.