Ammonia-induced pyrolytic conversion of a vinylic polysilane to silicon nitride

Abstract

sible that as lithium is being removed from the structure the anti-site defect concentration is increased, blocking the lithium diffusion paths and making subsequent lithium intercalation/deintercalation more difficult or even impossible.40,41 This may also be a source of irreversibility in the electrochemical reactions. under contract DE-AC02-76CH0001 to D. E. Cox.

Molecular Chemistry and Engineering of Boron‐Modified Polyorganosilazanes as New Processable and Functional SiBCN Precursors

“…PSZ exhibits three different weight losses during pyrolysis, in agreement with data reported for polyorganosilazanes . The first major weight loss occurs up to 250 °C, which mainly corresponds to the volatilization of low‐molecular‐weight organosilicon species, but also crosslinking reactions of the precursor through transamination and bond redistribution .…”

“…For sample BPSZ 30 _2 , the absorption bands due to the vinyl groups at around 1600 (C=C stretching) and 3050 cm −1 (C−H stretching) disappeared with a concomitant decrease in the intensity of the signal at around 1400 cm −1 (typical of SiCH=CH 2 units), which indicated the decomposition of the vinyl groups. Simultaneously, the intensity of the Si−H vibration signal at 2120 cm −1 became weaker, which indicated that hydrosilylation reactions between the Si−H bonds and SiCH=CH 2 units occurred and led to the formation of carbosilane chains. For sample BPSZ 3.75 _2 , the absorption band due to the B−H bonds vanished, which indicated their decomposition.…”

Nanocomposites through the Chemistry of Single‐Source Precursors: Understanding the Role of Chemistry behind the Design of Monolith‐Type Nanostructured Titanium Nitride/Silicon Nitride

“…So far,n oc omprehensive studies have been undertaken on the pyrolysis behavior of polytitanosilazanes in an ammonia atmosphere, and only af ew exist for polycarbosilanes and polycarbosilazanes. [49][50][51] Mutin et al [49] showedt hat SiH, SiCH 3 ,a nd SiCH 2 Si units in polycarbosilazane are easily modified by using ammonia,a ccording to Equation (1). This mechanism is quite favored with polymers that contain SiH units,w hich are sensitive to nucleophilic substitution.…”

Facile Synthesis of Si3N4 Nanocrystals Via an Organic–Inorganic Reaction Route

“…T HE high mechanical properties, thermal shock resistance, wear resistance, corrosion resistance, chemical stability, and excellent creep resistance of silicon nitride (Si 3 N 4 ) make it an attractive material in many fields, especially for high-temperature engineering applications. [1][2][3] The excellent performances and wide applications stimulate the exploitation in synthesis methods, and a lot of methods have so far been developed to prepare Si 3 N 4 , such as direct nitridation, [4][5][6] carbothermal reduction, 7,8 vapor phase reaction, 9 thermal decomposition, [10][11][12] silicon diimide pyrolysis, 13 combustion synthesis, 14,15 and solvothermal synthesis. 16 Very recently, several new routes have been proposed to prepare Si 3 N 4 .…”