SRBSN

SRBSN sintered reaction bonded Si3N4 ceramics ... 

Material SSN GPSN HPSN HIP-SSN, Sinter-HIP-SN HIP-SN RBSN SRBSN, HIP-SRBSN... 

By a post sintering process including additional sintering aids RBSN can densified to porosities of about 0-5% [538-540] This material, SRBSN, is applied for different wear parts [540]. A comparison of the production and material properties is given in Table 10. 

Mikijeli B, Mangels J (2001) SRBSN Material Development For Automotive Applications. In Heinrich JG, Aldinger F (eds) Ceramic Materials Components for Engines, Wiley-VCH, Weinheim, p 393... 

Material type Reaction bonded silicon nitride (RBSN) Sintered RBSN (SRBSN) Sintered silicon nitride (SSN) Gas pressure sintered silicon nitride (GPSN) Hot-pressed silicon nitride (HPSN) Sinter HIP silicon nitride (Sinter-HIPSN) HIP-ed silicon nitride HIP-SN... 

The experiments were conducted on a vertical rotary surface grinder with a 5.5 kW motor spindle. The feed can be continuously adjusted within a range. The workpieces were made from intered sintered reaction-bonded silicon nitride (SRBSN) and cast-and-sintered silicon nitride (Si3N4). The grain size was between 0.3 and 0.4 pm for SRBSN and between 0.6 and 0.8 pm for SiaN4. Cast-iron fiber-bonded diamond wheels of 200 mm diameter were used. A Noritake AFG-M grinding fluid at a rate of 20-30 L/min was used as electrolytic fluid. 

Better surface finish characterizes SRBSN when compared with SiaN4, especially with rougher wheels. 

Similar surface finish characterizes SRBSN and SisN4 when finer wheels were used. 

G. D. Quinn, L. K, Ives, S. Jahanmir, On the Nature of Machining Cracks in Ground Ceramics Part 1 SRBSN Strengths and Fractographic Analysis, Machining Science and Technology, 9, 169 - 210 (2005). 

Figure 16.13 Relationship between thermal conductivity and four-point bending strength of various types of high-thermal conductivity Si3N4 fabricated by different routes. GPSN = gas-pressure-sintered silicon nitride SRBSN = sintered reaction-bonded silicon nitride [62].

In addition to the above-mentioned benefits, the SRBSN process has the potential to fabricate silicon nitrides with enhanced mechanical and thermal properties. A typical example of the morphological change before and after the nitridation of a Si powder compact is shown in Figure 16.14 where, clearly, the particle size of the nitrided compact is much finer than that of the starting Si powder. This phenomenon, combined with the higher density achieved in nitrided compacts, makes the RB process very attractive for fabricating high-performance silicon nitride ceramics. 

Table 16.5 Characteristics of raw Si powders used for the preparation of sintered reaction-bonded silicon nitrides (SRBSN) and theirthermal conductivities (for comparison, the properties of normal sintered Si3N4 are also shown) [60].

Figure 16.15 Scanning electron microscopy images of polished and etched surfaces for (a) sintered reaction-bonded silicon nitride (SRBSN) from a fine silicon powder (b) SRBSN from a coarse Si powder (c) Sintered silicon nitride from a commercial fine-grained a-Si3N4 powder. All of the specimens were doped with...

Since the 1970s, the search for improved materials has led to a better understanding of the role of additives in the densification and microstructural development of silicon nitride-based ceramics and the consequences for final properties [1, 6]. Improvements in powder manufacture and forming techniques and the development of alternative firing processes has led to a complete family of materials including RBSN, HPSN, sintered silicon nitride (SSN), sintered reaction-bonded silicon nitride (SRBSN), gas-pressure sintered silicon nitride (GPSSN), hot isostatically pressed silicon nitride (HIPSN) and silicon nitride alloys or solid solutions termed SiAlONs, based on their elemental components. 

Values for ceramics range from below 1 for glasses and most single crystals 1 to 3 for glass-ceramics, clay-based ceramics and MgO 2.5. to 4 for early engineering ceramics (alumina, boron carbide, silicon carbides, RBSN) 4 to 6 for hot-pressed silicon nitride and SRBSN and for transformation-toughened alumina... 

Squint. A building brick with one end chamfered on both edges so that the brick can be used at an oblique quoin. SRBSN. Sintered Reaction-Bonded Silicon Nitride. 

Silicon Nitride Compacts A flow chart of the production routes for porous reaction-bonded siUcon nitride (RBSN), dense sintered siUcon nitride (SSN), and sintered reaction-bonded siUcon nitride (SRBSN) is shown in Figure 11.15. 

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