Article

Rowell R.M., Andersone I., Andersons B. 2012. Heat treatment. Chapter 14 in Handbook of Wood Chemistry and Wood Composites. Second Edition, CRC Press, 511-536.

January 2012

Authors:

Ingeborga Andersone

Latvian State institute of Wood chemistry

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ResearchGate has not been able to resolve any references for this publication.

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Comparison of EMC and durability of heat treated wood from high versus low water vapour pressure rea...

February 2015 · International Wood Products Journal

A large number of different heating technologies has been put into use for industrial scale thermal modification of wood. A useful classification of these processes is by the level of water vapour pressure, which ranges from vacuum to high saturated steam pressures. Only high water vapour pressure systems can maintain a finite moisture content during the heat treatment, but little is known about ... [Show full abstract] the water vapour pressure dependence of the thermal modification chemistry and the resulting modified wood properties. It is concluded from our analysis that the thermal wood reaction chemistry at the molecular functional group level is quite independent of the process and wood species. Wood properties that are strongly determined by wood chemical composition, such as the fungal durability and the equilibrium moisture content (EMC), can hence be equally achieved by all processes and for all wood species. This finding cannot be transferred to every other thermally modified wood property.

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Properties after weathering and decay resistance of a thermally modified wood structural board

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This paper aims to evaluate whether a thermal post-treatment can be applied to enhance the performance of oriented strandboard (OSB). Samples from 42 commercial OSBs were heat-treated at two temperature levels (190 and 220 °C) and for three heating times (12, 16, and 20 min) using a single opening hot-press. For comparison, control boards were kept untreated. These samples were exposed for eight ... [Show full abstract] months to outdoor weathering, and then their physical and mechanical properties were evaluated, as was their decay resistance against the brown-rot (Gloeophyllum trabeum [Persoon ex Fries] Murrill) and white-rot (Trametes versicolor [Linnaeus ex Fries] Pilat Murrill) fungi. The results indicated that the heat-treated samples maintained their mechanical properties at a much higher level after weathering than did the untreated ones. It was determined that the higher the treatment temperature, the better the residual mechanical properties. The proposed thermal treatment also slightly improved the decay resistance against the two evaluated fungi, but it was not enough to change the resistance class of the OSB.

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Handbook of Plastic Optics: Second Edition

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S. Bäumer

A coherent overview of the current status of injection molded optics, describing in detail all aspects of plastic optics, from design issues to production technology and quality control. This updated second edition is supplemented by a chapter on the equipment and process of injection wells as well as a look at recent applications. The contributors, each one a leading expert in their discipline, ... [Show full abstract] have either a background in or strong ties to the industry, thus combining a large amount of practical experience. With its focus firmly set on practical applications, this is an indispensable reference for all those working in optics research and development. .

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Effect of heat on the mechanical properties of wood and wood composites

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A critical aspect of fire resistant design is assessing the post-fire residual strength of the materials in the existing structures. As wood and wood-based composites are being used heavily in single family residential dwellings in the US, it is highly imperative to categorize their response when exposed to elevated temperatures for a sustained period of time. The objective of this study are (a) ... [Show full abstract] to study the effect of temperature and exposure time on bending strength (MOR) and stiffness (MOE) of solid sawn lumber (SSL), laminated veneer lumber (LVL), oriented strand board (OSB) and plywood and (b) to develop predictive relationships between different temperature and time of exposure using a regression based model for thermal degradation of strength. A total of 1080 samples were tested in static bending under various heat treatments. The results indicated that exposure to elevated temperature caused significant degradation of bending strength and stiffness. The highest degradation occurred when exposed to 200°C for 2 hours. A statistical regression based model was developed and evaluated for predicting the strength loss of wood and wood-based composites as a function of thermal exposure temperature and time of exposure.

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Hybrid Ceramic Matrix Composites: A Study of Transverse Properties and Failure Modes

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The purpose of this study was to demonstrate the effects, and ultimately, the advantages of forming a hybrid ceramic matrix composite (HCMC) by adding whiskers to a fiber reinforced ceramic matrix composite (FCMC). The addition of whiskers to a continuous fiber ceramic composite has been shown to produce a hybrid composite that: (1) is more stiffer, (2) resists microcracking until higher loading ... [Show full abstract] levels, (3) has improved transverse strength and stiffness and (4) shows improved damage tolerance when compared with fiber reinforced composites (FCMC). The modulus was found to be, on average, 212 + or - 24 GPa for the hybrid system compared to 170 + or - 20 GPa for the FCMC system. The ultimate strength was basically preserved, but the stress at which microcracking was first observed was increased for the hybrid system to 121.4 + or - 19.0, an increase almost threefold over the FCMC system. The transverse microcracking stress was 31.0 + or - 7.0 MPa for the HCMC compared with 16.4 + or - 1.0 MPa for the FCMC. The ultimate strengths were 62.4 + or - 7.0 MPa and 24.2 + or - 6.0 MPa, respectively. The study has indeed demonstrated the benefits from hybridization of ceramic composites and provide a basis for further study. (MM)

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Influences of Both Carbon Supports and Heat‐Treatment of Supported Catalyst on Electrochemical Oxida...

August 1995 · Journal of The Electrochemical Society

The effects of carbon supports for platinum‐ruthenium (Pt‐Ru) catalysts on anode performance of direct methanol fuel cells (DMFC) were investigated. Good polarization characteristics of the methanol electrode were obtained for a Pt‐Ru catalyst supported on an acetylene black with high specific surface area and a pore size distribution in the range of 3 to 8 nm. The performance of the methanol ... [Show full abstract] electrode increased with the increase in pore volume for the pore size distribution of 3 to 8 nm. Analyses of various carbon blacks and supported catalysts were carried out with several techniques: adsorption (Brunauer‐Emmett‐Teller (BET) and Barrett‐Joyner‐Halenda (BJH) methods), adsorption, transmission electron microscope, and scanning electron microscope observations. The effects of the heat‐treating temperature, time, and atmosphere on the polarization curves of the methanol electrodes with the acetylene black were investigated. The heat‐treatment in air at 370°C improved not only methanol oxidation but the durability of the Pt‐Ru catalyst.

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Adaptive Wood Composite: Experiment

May 2003 · Journal of Structural Engineering

Adaptive wood composites consisting of wood and piezoelectric materials are investigated experimentally. Two physical samples of adaptive composites are constructed and tested to determine the levels of adaptive actuation. To actuate the composites, electric fields are applied to the piezoelectric layer, inducing strain in the composites. These experimental results are compared with those ... [Show full abstract] predicted by a mathematical model, the agreement between the theory and experiment is determined, and the limits in their construction are assessed.

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Lightweight stainless steel foams approaching 10% theoretical density are being fabricated via direct reduction. These foams are formed using a coaxial nozzle process that generates hollow ceramic spheres at high rates from an acetone-based slurry. The Fe2O3/Cr2O3 hollow spheres are reduced in a hydrogen/argon atmosphere at high temperature resulting in individual hollow metal spheres. Using more ... [Show full abstract] viscous slurry of similar composition, the spheres are bonded at points of contact into a quasi-closed cell structure and further heat treated to reduce the bond phase. The result is a Fe-12Cr alloy hollow sphere foam with a density on the order of 1 g/cc. Addition of carbon and further heat treatments allow the control of strength and ductility through micro structure. Mechanical testing is being conducted to determine attainable properties that can be compared to existing foam models.

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Reaction Mechanism of H3BO3ZnO Bonding Material Under Hot-Pressing and Heat Treatment

November 1981 · Journal of the American Ceramic Society

The bonding material H3BO3-ZnO was used to form a composite with fiberglass mats. The composite is formed by hot-pressing at 180°C and is then heat-treated for durability. The bonding material becomes liquid during hot-pressing. Heat treatment promotes the reaction between H3BO3 and ZnO and converts the bonding phase to a primarily amorphous state containing a small amount of crystalline material.

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Poly(vinylidene chloride)-Based Carbon as an Electrode Material for High Power Capacitors with an Aq...

October 2001 · Journal of The Electrochemical Society

The specific capacitance (F/g) of a poly(vinylidene chloride) (PVDC)-based electric double-layer capacitor (EDLC) carbon electrode prepared by heat-treatment at only 700°C shows a capacitance as high as 64 F/g at 1 mA output current density, although it shows a specific surface area of only 700 m2/g, smaller than those of other conventional activated carbon fibers and activated carbons. To ... [Show full abstract] elucidate the relationship between the specific capacitance and the pore structure for PVDC-based carbons, from an EDLC practical applications viewpoint, structural characterization was performed using various techniques. PVDC-based carbon had sufficient porosity during the carbonization process without any additional activation process for use as an EDLC electrode. It has been shown that the strongest peak in the pore size distribution is at a diameter around 9 Å. The most probable electrolyte ion sizes, solvated as the hydrated ions in aqueous solution, have been obtained by computer simulation as 9 Å. This range of electrolyte ion sizes is highly convenient for entering the pores of the present PVDC-based carbons to establish the electric double layer at the pore wall. Furthermore the evolution of and HCl during the carbonization of PVDC creates rich open pores with nanometer dimensions connecting to the free surface of the particles in the samples. It is concluded that the higher specific capacitance of PVDC-based carbons, compared to conventional activated carbons in aqueous electronic double-layer capacitors, is due to their optimal pore size distribution. The present precursor has been shown to be a promising material for high power EDLC applications. © 2001 The Electrochemical Society. All rights reserved.

Article

Effects of Molybdenum and Age Hardening on the Corrosion Resistance of Chromium Alloyed Maraging Ste...

March 1973

Potentiokinetic and potentiostatic current density/potential curves are plotted for four nominally 15Cr-8. 5Co-4. 5Ni-0. 2Ti steels with about 1, 2, 3, and 4% Mo, respectively, in comparison with a 12Cr-8Ni-5Co-2Mo and an austenitic 18Cr-11Ni steel. The maraging steels were aged at 500 C for up to 500 hr and water quenched. The corroding media were dilute H//2SO//4 and artificial sea water. The ... [Show full abstract] results obtained are interpreted in terms of the effects of heat treatment and composition on the structure of the steels. Corrosion resistance increased with increasing molybdenum.

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TEM investigations of the fibre/matrix interface in SCS-6 Sic/Ti-25Al-10Nb-3V-1Mo composites

October 1998 · Composites Part A Applied Science and Manufacturing

Interfacial reactions in SCS-6 SiC/Ti–25Al–10Nb–3V–1Mo composites processed by fibre coating with matrix material, hot isostatic pressing and thermal treating for simulation of service conditions were studied by analytical transmission electron microscopy. In the as-processed specimen three reaction layers were observed. Adjacent to C coating of the SCS-6 fibre no mixture of TiC and Ti5Si3 was ... [Show full abstract] found reported in literature [Rhodes, C. G., Mat. Res. Soc. Symp. Proc., 1992, 273, 17; Baumann, S. F., Brindley, P. K. and Smith, S. D., Metall. Trans., 1990, 21A, 1559; Smith, P. R., Rhodes, C. G. and Revelos, W. C., in Interfaces in Metal–Ceramics Composites, eds R. Y. Lin, R. J. Arsenault, G. P. Martins and S. G. Fishman, TMS Press, New York, 1989, pp. 35–58; Badini, C., Terraris, M. and Marchetti, F., J. Mater. Sci., 1994, 2]. Instead, two sublayers were determined. Sublayer 1 close to C coating was identified as (Ti,V)C and sublayer 2 as (Ti,V,Nb)5Si3. The second layer is composed of larger equiaxed grains of (Ti,Nb)C and separated from matrix by a third layer of (Ti,Nb)5(Si,Al)3. Small amounts of (Ti,Nb)3(Si,Al) and (Ti,Nb)3(Al,Si)C were also identified. In the specimens heat treated at 700°C and 800° for up to 3000h, three, four or five reaction layers were found. In all specimens the reaction products of the first two layers are the same. The additional layers consist of the (Ti,Nb)3(Al,Si)C, the (Ti,Nb)3(Si,Al) or the (Ti,Nb)5(Si,Al)3 phase. These phases are arranged in different sequences. At the treatment temperature of 700°C the thickening of the interfacial reaction zone is mainly due to the growth of (Ti,Nb)3(Al,Si)C and (Ti,Nb)3(Si,Al). The growth of these phases is probably responsible for the slow decrease of mechanical properties of the composites during heat treatment. A kinetic analysis indicates that the growth of the reaction zone is a diffusion controlled process. The activation energy was determined to be 368kJ/mol for the total reaction zone, 302kJ/mol for (Ti,Nb)3(Al,Si)C and 181kJ/mol for (Ti,Nb)3(Si,Al) phase. The experimental results and a crystallographic analysis indicate that (Ti,Nb)3(Si,Al) is not a diffusion barrier for the carbon and titanium diffusion.

Last Updated: 05 Jul 2022

Rowell R.M., Andersone I., Andersons B. 2012. Heat treatment. Chapter 14 in Handbook of Wood Chemistry and Wood Composites. Second Edition, CRC Press, 511-536.

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