New Materials in the System Si-(N,C)-B and Their Characterization

Baldus, H. P.; Jansen, Martin; Wagner, O.

doi:10.4028/www.scientific.net/kem.89-91.75

Cited by 61 publications

(71 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…So, it was only possible to determine the average structure with a Cl : C ratio of nearly 1 : 2. Thus, the calculated B-Cl/C bond lengths of 1.678(4) and 1.689(2) Å are too long for pure B-C bonds like in 2,4,6-trimethylborazine (1.52 Å [33]), and too short for pure B-Cl bonds as found in 2,4,6-trichloroborazine (1.76 Å [34]) or in [(Si(CH 3 ) 3 )NBCl] 3 (1.79 Å [22]). The protons of the boron bonded methyl groups were localized in difference fourier maps during the structure solution, however, due to the mentioned mixed occupation, refinement of these positions was not possible.…”

Section: Resultsmentioning

confidence: 99%

“…Synthesis and characterization of monomer [(SiCl 3 )NB(Cl n (CH 3 ) 1-n )] 3 The synthesis of the borazine derivate [(SiCl 3 )NB(Cl n (CH 3 ) 1-n )] 3 (Scheme 1) consists of three steps starting with the transsilylation on hexamethyldisilazane (HMDS) to obtain 1,1,1-trichloro-3,3,3-trimethyldisilanzane (TTDS). In the following step the proton in TTDS is replaced by a dichloroboryl group using butyl lithium (BuLi) and BCl 3 resulting in dichloroboryl-(trichlorosilyl)-(trimethylsilyl)-amine (DTTA).…”

Section: Resultsmentioning

confidence: 99%

“…Therefore we have regarded it worthwhile to use molecular precursors, in which silicon is attached to a borazine core by nitrogen bridges. Here we report on the borazine derivatives [(SiCl 3 )NB(Cl n (CH 3 ) 1-n )] 3 , their characterization and transformation to an amorphous inorganic Si/B/N/C ceramic.…”

Section: Introductionmentioning

confidence: 99%

“…Single source molecular precursors of the general type R 1 R 2 R 3 Si-X-BR 4 R 5 with X = NH [1, [8][9][10], N(CH 3 ) [11][12][13], CH 2 [14,15], C 2 H 4 [16] and R 1 -R 5 = CH 3 or Cl have proven to perform particularly well with respect to versatility and quality of the final ceramic. As measured by the combination of properties relevant for an application as structural ceramics at high temperature, the Si/B/N/C ceramics show superior performance [6].…”

Section: Introductionmentioning

confidence: 99%

“…Random networks consisting of Si, B, N, and C represent a new class of ceramics that are exclusively accessible along a molecular -polymer precursor route [1][2][3][4][5][6][7]. Single source molecular precursors of the general type R 1 R 2 R 3 Si-X-BR 4 R 5 with X = NH [1, [8][9][10], N(CH 3 ) [11][12][13], CH 2 [14,15], C 2 H 4 [16] and R 1 -R 5 = CH 3 or Cl have proven to perform particularly well with respect to versatility and quality of the final ceramic.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Borazine Based Molecular Single Source Precursors for Si/B/N/C Ceramics

Schurz

Jansen

2010

Zeitschrift anorg allge chemie

Self Cite

View full text Add to dashboard Cite

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Borazine Based Molecular Single Source Precursors for Si/B/N/C Ceramics

Schurz

Jansen

2010

Zeitschrift anorg allge chemie

Self Cite

View full text Add to dashboard Cite

show abstract

Boron-modified polysilylcarbodi-imides as precursors for Si-B-C-N ceramics: Synthesis, plastic-forming and high-temperature behavior

Weinmann

Haug

Bill

et al. 1998

Appl. Organometal. Chem.

View full text Add to dashboard Cite

The synthesis, by two different reaction pathways, of boron-modified polysilylcarbodi-imides of general type {B[C 2 H 4 Si(R)NCN] 3 } n (R = singly bonded organic ligand) and the plasticforming and the thermal behavior of these polymers are described. Compounds {B[C 2 H 4 Si(R)NCN] 3 } n [2a, R = H; 2b, R = CH 3 ; 2c, R = (NCN) 0.5 ] can be obtained by treatment of the vinyl-substituted polysilylcarbodi-imides [(H 2 C=CH)(R)SiNCN] n [1a, R = H; 1b, R = CH 3 ; 1c, R = (NCN) 0.5 ] with borane dimethylsulfide BH 3 ÁS(CH 3) 2. The polysilylcarbodi-imides 1a-1c themselves are accessible via the reaction of vinyl-substituted chlorosilanes (H 2 C=CH)-(R)SiCl 2 with cyanamide H 2 N-CN in the presence of pyridine or by a non-oxide sol-gel process of vinylated chlorosilanes and bis(trimethylsilyl)carbodi-imide, (H 3 C) 3 SiN=C=N-Si(CH 3) 3. In the second method for the synthesis of 2a-2c, hydroboration of vinylsubstituted chlorosilanes (H 2 C=CH)(R)SiCl 2 with borane dimethylsulfide, borane trimethylamide or borane triethylamide to yield the tris[(chlorosilyl)ethyl]boranes B[C 2 H 4 Si(R)Cl 2 ] 3 (3a, R = H; 3b, R = CH 3 ; 3c, R = Cl) is followed by treatment of the as-obtained compounds with bis(trimethylsilyl)carbodi-imide, which results in the formation of the hydroborated polysilylcarbodi-imides 2a-2c. The thermogravimetric behavior of the polymers 1a-1c and 2a-2c up to 2300°C is reported. It is shown that boron-modified polysilylcarbodi-imides are suitable precursors for the preparation of dense bulk ceramics. Therefore, the preparation of green bodies of the hydroborated polysilylcarbodiimides 2a-2c by plastic forming (PF) is described. A series of experiments points to the fact that the microstructure of the as-obtained ceramic monoliths obtained by subsequent thermolysis of the plastic-formed green bodies is strongly influenced by the conditions during plastic forming.

show abstract

Sol-Gel-Process in the Ammono-System - a Novel Access to Silicon Based Nitrides

Löffelholz

Engering

Jansen

2000

Z. anorg. allg. Chem.

Self Cite

View full text Add to dashboard Cite

Controlled coammonolysis of elementalkylamides in aprotic organic solvents at low temperatures have been shown to result in the formation of polyazanes. The synthetic procedure developed may be addressed as “sol‐gel‐route in the ammono system”. Pyrolysis of these novel polymer precursors gave access to multinary nitrides. For the model systems Si(NHMe)4/B(NMe2)3, Si(NHMe)4/Ti(NMe2)4, and Si(NHMe)4/Ta(NMe2)5 polymeric boro‐, titano and tantalosilazanes were obtained. Pyrolysis in ammonia at 1000 °C yielded amorphous silicon boron nitride, silicon titanium nitride and silicon tantalum nitride powders; further heating of the nitride powders at 1500 °C in nitrogen atmosphere led to the formation of partly crystalline composites of α‐Si3N4 and amorphous silicon boron nitride for the Si/B/N system, a composite of finely dispersed TiN and amorphous silicon titanium nitride for the Si/Ti/N system, and crystalline TaN and amorphous silicon nitride for the Si/Ta/N system. Furthermore, the structure and pyrolysis chemistry of the polymeric intermediates, as well as the morphology of the pyrolysis products, were studied by NMR, MAS‐NMR, FT‐IR, DTA‐TG‐MS, XRD, SEM, EDX and elemental analyses.

show abstract

New Materials in the System Si-(N,C)-B and Their Characterization

Cited by 61 publications

References 0 publications

Borazine Based Molecular Single Source Precursors for Si/B/N/C Ceramics

Borazine Based Molecular Single Source Precursors for Si/B/N/C Ceramics

Boron-modified polysilylcarbodi-imides as precursors for Si-B-C-N ceramics: Synthesis, plastic-forming and high-temperature behavior

Sol-Gel-Process in the Ammono-System - a Novel Access to Silicon Based Nitrides

Contact Info

Product

Resources

About