scholarly journals Haptic and Aesthetic Properties of Heat-Treated Modified Birch Wood

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1081
Author(s):  
Vlastimil Borůvka ◽  
Přemysl Šedivka ◽  
David Novák ◽  
Tomáš Holeček ◽  
Jiří Turek
Keyword(s):  
Thermal Conductivity ◽  
Heat Treatment ◽  
Heat Capacity ◽  
Moisture Content ◽  
Thermal Characteristics ◽  
Treated Wood ◽  
Treatment Temperature ◽  
Birch Wood ◽  
Positive Perception ◽  
Heat Treated

This paper deals with the effect of heat treatment on the selected physical properties of birch wood. Five stages of heat treatment were used, ranging from 160 °C to 200 °C, in 10 °C increments, having a peak treatment duration of 3 h for each level. Primarily, changes in thermal characteristics, namely conductivity, diffusivity, effusivity, volume heat capacity, changes in colour and gloss parameters, mass loss due to modification and different moisture content in wood under given equilibrium climatic conditions, were monitored. The ISOMET 2114 analyser was used to measure the thermal characteristics. The measurement principle of this analyser is based on the analysis of the thermal response of the analysed material to pulses of heat flow. Measurements of colour, gloss, density and moisture content were carried out according to harmonised EN standards. The aim was to experimentally verify the more or less generally known more positive perception of heat-treated wood, both by touch and sight, i.e., the warmer perception of darker brown shades of wood. In terms of thermal characteristics, the most interesting result is that they gradually decrease with increasing treatment temperature. For example, at the highest treatment temperature of 200 °C, there is a decrease in thermal conductivity by 20.2%, a decrease in volume heat capacity by 15.0%, and a decrease in effusivity by 17.7%. The decrease in thermal conductivity is nearly constant at all treatment levels, specifically at this treatment temperature, by 6.0%. The fact mentioned above is positive in terms of the tactile perception of such treated wood, which can have a positive effect, for example, in furniture with surface application of heat-treated veneers, which are perceived positively by the majority of the human population visually or as a cladding material in saunas. In this context, it has been found that the thermal modification at the above-mentioned treatment temperature of 200 °C results in a decrease in brightness by 44.0%, a decrease in total colour difference by 38.4%, and a decrease in gloss (at an angle of 60°) by 18.2%. The decrease in gloss is only one essential negative aspect that can be addressed by subsequent surface treatment. During the heat treatment, there is also a loss of mass in volume, e.g., at a treatment temperature of 200 °C and subsequent conditioning to an equilibrium moisture content in a conditioning chamber with an air temperature of 20 ± 2 °C and relative humidity of 65 % ± 5%, there was a decrease by 7.9%. In conclusion, the experiments clearly confirmed the hypothesis of a positive perception of heat-treated wood in terms of haptics and aesthetics.

scholarly journals Effects of aluminum sulfate soaking pretreatment on dimensional stability and thermostability of heat-treated wood

2020 ◽  
Author(s):  
Lijie Qu ◽  
Zhenyu Wang ◽  
Jing Qian ◽  
Zhengbin He ◽  
Songlin Yi
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Thermal Degradation ◽  
Structural Changes ◽  
Aluminum Sulfate ◽  
Treated Wood ◽  
Treatment Temperature ◽  
Chinese Fir ◽  
Heat Treated ◽  
Thermal Stability Of

Abstract Acidic aluminum sulfate hydrolysis solutions can be used to catalyze the thermal degradation of wood in a mild temperature environment, and thus reduce the temperature required for heat treatment process. To improve the dimensional and thermal stability of Chinese fir during heat treatment at 120 °C, 140 °C and 160 °C, this study investigated the effects of soaking pretreatment with 5%, 10% and 15% aluminum sulfate on the chemical and structural changes of the heat-treated Chinese fir. The results indicated that the samples treated at 15% aluminum sulfate concentration and 160 °C heat treatment achieved the best dimensional and thermal stability. Chemical analyses by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) indicated that the catalysis of aluminum sulfate resulted in degradation of hemicelluloses during the heat treatment, and an increase in the soaking concentration and heat treatment temperature also affected the thermal degradation of celluloses. The scanning electron microscope (SEM) and mass changes test results proved that the hydrolyzed aluminum flocs mainly adhered to the inner wall of the wood tracheid as spherical precipitates, and when the soaking concentration reached 10% and 15%, a uniform soaking effect could be achieved. The thermogravimetric (TG) analysis revealed the soaking pretreatment effectively improved the thermal stability of the heat-treated wood by physically wrapping and promoting the formation of a carbon layer on the wood surface during heat treatment. Thus, aluminum sulfate soaking pretreatment exerted a great effect on the dimensional and thermal stability of wood, allowing heat treatment to be performed at a lower temperature.

scholarly journals Enhancing Graphene Retention and Electrical Conductivity of Plasma-Sprayed Alumina/Graphene Nanoplatelets Coating by Powder Heat Treatment

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 643
Author(s):  
Xiaoyu Wu ◽  
Shufeng Xie ◽  
Kangwei Xu ◽  
Lei Huang ◽  
Daling Wei ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Electrical Conductivity ◽  
Structural Integrity ◽  
Ceramic Coatings ◽  
Treatment Temperature ◽  
Graphene Nanoplatelets ◽  
Structural Defects ◽  
Temperature Plasma ◽  
Heat Treated ◽  
Plasma Sprayed

Burning loss of graphene in the high-temperature plasma-spraying process is a critical issue, significantly limiting the remarkable performance improvement in graphene reinforced ceramic coatings. Here, we reported an effective approach to enhance the graphene retention, and thus improve the performance of plasma-sprayed alumina/graphene nanoplatelets (Al2O3/GNPs) coatings by heat treatment of agglomerated Al2O3/GNPs powders. The effect of powder heat treatment on the microstructure, GNPs retention, and electrical conductivity of Al2O3/GNPs coatings were systematically investigated. The results indicated that, with the increase in the powder heat treatment temperature, the plasma-sprayed Al2O3/GNPs coatings exhibited decreased porosity and improved adhesive strength. Thermogravimetric analysis and Raman spectra results indicated that increased GNPs retention from 12.9% to 28.4%, and further to 37.4%, as well as decreased structural defects, were obtained for the AG, AG850, and AG1280 coatings, respectively, which were fabricated by using AG powders without heat treatment, powders heat-treated at 850 °C, and powders heat-treated at 1280 °C. Moreover, the electrical conductivities of AG, AG850, and AG1280 coatings exhibited 3 orders, 4 orders, and 7 orders of magnitude higher than that of Al2O3 coating, respectively. Powder heat treatment is considered to increase the melting degree of agglomerated alumina particles, eventually leaving less thermal energy for GNPs to burn; thus, a high retention amount and structural integrity of GNPs and significantly enhanced electrical conductivity were achieved for the plasma-sprayed Al2O3/GNPs coatings.

scholarly journals Water Resistance and Creep Behavior of Heat-Treated Moso Bamboo Determined by the Stepped Isostress Method

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1264
Author(s):  
Teng-Chun Yang ◽  
Tung-Lin Wu ◽  
Chin-Hao Yeh
Keyword(s):  
Heat Treatment ◽  
Water Absorption ◽  
Creep Behavior ◽  
Heat Treatment Temperature ◽  
Water Resistance ◽  
Absorption Efficiency ◽  
Treatment Temperature ◽  
Moso Bamboo ◽  
Phyllostachys Pubescens ◽  
Heat Treated

The influence of heat treatment on the physico-mechanical properties, water resistance, and creep behavior of moso bamboo (Phyllostachys pubescens) was determined in this study. The results revealed that the density, moisture content, and flexural properties showed negative relationships with the heat treatment temperature, while an improvement in the dimensional stability (anti-swelling efficiency and anti-water absorption efficiency) of heat-treated samples was observed during water absorption tests. Additionally, the creep master curves of the untreated and heat-treated samples were successfully constructed using the stepped isostress method (SSM) at a series of elevated stresses. Furthermore, the SSM-predicted creep compliance curves fit well with the 90-day full-scale experimental data. When the heat treatment temperature increased to 180 °C, the degradation ratio of the creep resistance (rd) significantly increased over all periods. However, the rd of the tested bamboo decreased as the heat treatment temperature increased up to 220 °C.

Effect of Heat Treatment on the Microstructure and Property of TiAl Alloys Prepared by Gas Atomization Powders

2013 ◽  
Vol 747-748 ◽  
pp. 497-501
Author(s):  
Na Liu ◽  
Zhou Li ◽  
Guo Qing Zhang ◽  
Hua Yuan ◽  
Wen Yong Xu ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Heat Treatment Temperature ◽  
Tial Alloy ◽  
Lamellar Microstructure ◽  
Treatment Temperature ◽  
Gas Atomization ◽  
Thermally Induced ◽  
Heat Treated ◽  
Fine Duplex ◽  
Step Heat Treatment

Powder metallurgical TiAl alloy was fabricated by gas atomization powders, and the effect of heat treatment temperature on the microstructure evolution and room tensile properties of PM TiAl alloy was investigated. The uniform fine duplex microstructure was formed in PM TiAl based alloy after being heat treated at 1250/2h followed by furnace cooling (FC)+ 900/6h (FC). When the first step heat treatment temperature was improved to 1360/1h, the near lamellar microstructure was achieved. The ductility of the alloy after heat treatment improved markedly to 1.2% and 0.6%, but the tensile strength decreased to 570MPa and 600MPa compared to 655MPa of as-HIP TiAl alloy. Post heat treatment at the higher temperature in the alpha plus gamma field would regenerate thermally induced porosity (TIP).

Mechanical and Superelastic Properties of Au-51Ti-18Co Biomedical Shape Memory Alloy Heat-Treated at 1173 K to 1373 K

2016 ◽  
Vol 97 ◽  
pp. 141-146 ◽  
Author(s):  
Taywin Buasri ◽  
Hyunbo Shim ◽  
Masaki Tahara ◽  
Tomonari Inamura ◽  
Kenji Goto ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Heat Treatment Temperature ◽  
Critical Stress ◽  
Biomedical Applications ◽  
Shape Recovery ◽  
Treatment Temperature ◽  
Recovery Ratio ◽  
Recovery Strain ◽  
Heat Treated ◽  
Alloy Heat

The effect of heat treatment temperature from 1173 K to 1373 K for 3.6 ks on mechanical and superelastic properties of an Ni-free Au-51Ti-18Co alloy (mol%) was investigated. The stress for inducing martensitic transformation (SIMT) and the critical stress for slip deformation (CSS) slightly decrease with increasing the heat–treatment temperature. Regardless of heat–treatment temperature, good superelasticity was definitely recognized with the maximum shape recovery ratio up to 95 % and 4 % superelastic shape recovery strain. As the mentioned reasons, the Au-51Ti-18Co alloy is promising for practical biomedical applications.

Comparison of the color and weight change in Paulownia tomentosa and Pinus koraiensis wood heat-treated in hot oil and hot air

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 5574-5585
Author(s):  
Intan Fajar Suri ◽  
Jong Ho Kim ◽  
Byantara Darsan Purusatama ◽  
Go Un Yang ◽  
Denni Prasetia ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Color Change ◽  
Treated Wood ◽  
Pinus Koraiensis ◽  
Weight Changes ◽  
Paulownia Tomentosa ◽  
Wood Color ◽  
Color Changes ◽  
Hot Air ◽  
Heat Treated

Color changes were tested and compared for heat-treated Paulownia tomentosa and Pinus koraiensis wood treated with hot oil or hot air for further utilization of these species. Hot oil and hot air treatments were conducted at 180, 200, and 220 °C for 1, 2, and 3 h. Heat-treated wood color changes were determined using the CIE-Lab color system. Weight changes of the wood before and after heat treatment were also determined. The weight of the oil heat-treated wood increased considerably but it decreased in air heat-treated wood. The oil heat-treated samples showed a greater decrease in lightness (L*) than air heat-treated samples. A significant change in L* was observed in Paulownia tomentosa. The red/green chromaticity (a*) of both wood samples increased at 180 and 200 °C and slightly decreased at 220 °C. The yellow/blue chromaticity (b*) in both wood samples increased at 180 °C, but it rapidly decreased with increasing treatment durations at 200 and 220 °C. The overall color change (ΔE*) in both heat treatments increased with increasing temperature, being higher in Paulownia tomentosa than in Pinus koraiensis. In conclusion, oil heat treatment reduced treatment duration and was a more effective method than air heat treatment in improving wood color.

Sensitivity of Thermal Conductivity of Carbon Nanotubes to Defect Concentrations and Heat-Treatment

2012 ◽  
Author(s):  
Michael F. P. Bifano ◽  
Jungkyu Park ◽  
Vikas Prakash
Keyword(s):  
Thermal Conductivity ◽  
Heat Treatment ◽  
Interatomic Potential ◽  
Side Wall ◽  
Chemical Vapor ◽  
Md Simulations ◽  
Heat Treated ◽  
Side Walls ◽  
Non Equilibrium Molecular Dynamics ◽  
Vacancy Concentrations

In the present study, classical MD simulations using reverse non-equilibrium molecular dynamics with the AIREBO interatomic potential are used to investigate the sensitivity of thermal conductivity in SWCNTs to side-wall defect concentration and heat-treatment. Two types of defects are investigated. First, the thermal conductivity of (6,6) SWCNTs is obtained as a function of concentration of chemisorbed hydrogen adatoms. Secondly, the thermal conductivity is obtained as a function of point-vacancy concentrations. The results of the studies show that 2 atom% of hydrogenation and 1.5–2% vacancy concentrations have very similar detrimental effects on the thermal conductivity of SWCNT. Vacancy repair is evident with heat treatment, and heat-treatments at 3000°C for up to 22 ns are found to transform point vacancies into various types of non-hexagonal side-wall defects; this vacancy repair is accompanied by a ca. 10% increase in thermal conductivity. Thermal conductivity measurements in both heat-treated and non-heat treated chemical vapor deposition grown MWCNTs are also reviewed. The results suggest that CNT thermal conductivity can be drastically increased if measures are taken to remove common defects from the SWCNT side-walls.

Investigation of Heat Treated Electrodeposited CoNiFe on Microstructure and Hardness

2015 ◽  
Vol 1113 ◽  
pp. 56-61
Author(s):  
Nor Azrina Resali ◽  
Koay Mei Hyie ◽  
M.N. Berhan ◽  
C.M. Mardziah
Keyword(s):  
Heat Treatment ◽  
Heat Treatment Temperature ◽  
Treatment Temperature ◽  
Crystallographic Structure ◽  
Face Centered Cubic ◽  
Heat Treated ◽  
Hardness Property ◽  
Finishing Process ◽  
The Face ◽  
Face Centered

In this research, heat treatment is the final finishing process applied on nanocrystalline CoNiFe to improve microstructure for good hardness property. Nanocrystalline CoNiFe has been synthesized using the electrodeposition method. This study investigated the effect of heat treatment at 500°C, 600°C, 700°C and 800°C on electrodeposited nanocrystalline CoNiFe. The heat treatment process was performed in the tube furnace with flowing Argon gas. By changing the heat treatment temperature, physical properties such as phase and crystallographic structure, surface morphology, grain size and hardness of nanocrystalline CoNiFe was studied. The nanocrystalline CoNiFe phase revealed the Face Centered Cubic (FCC) and Body Centered Cubic (BCC) crystal structure. FESEM micrographs showed that the grain sizes of the coatings were in the range of 78.76 nm to 132 nm. Dendrite shape was found in the microstructure of nanocrystalline CoNiFe. The nanocrystalline CoNiFe prepared in heat treatment temperature of 700°C, achieved the highest hardness of 449 HVN. The surface roughness of nanocrystalline CoNiFe heated at 700°C was found to be smaller than other temperatures.

scholarly journals COLOR CHANGE — MASS LOSS CORRELATION FOR HEAT-TREATED WOOD

2014 ◽  
Vol 2 ◽  
pp. 345-352 ◽  
Author(s):  
Cristina Marinela Olarescu ◽  
Mihaela Campean
Keyword(s):  
Heat Treatment ◽  
Mass Loss ◽  
Color Change ◽  
Treated Wood ◽  
Untreated Wood ◽  
Cost Effective ◽  
Assessment Procedure ◽  
Mathematical Correlation ◽  
Heat Treated ◽  
Two Parameters

Heat treatment is renowned as the most environmentally friendly process of dimensional stabilization that can be applied to wood, in order to make it suitable for outdoor uses. It also darkens wood color and improves wood durability. The intensity of heat treatment can be appreciated by means of two parameters: the color change occured in wood due to the high temperature, and the mass loss, which is a measure of the degree of thermal degradation. In order to find a mathematical correlation between these two parameters, an experimental study was conducted with four European wood species, which were heat-treated at 180°C and 200ºC, for 1-3 hours, under atmosheric pressure.The paper presents the results concerning the color changes and mass losses recorded for the heat-treated wood samples compared to untreated wood.  For all four species, the dependency between the color change and the mass loss was found to be best described by a logarithmic regression equation with R2 of 0.93 to 0.99 for the soft species (spruce, pine and lime), and R2 of 0.77 for beech. The results of this study envisage to simplify the assessment procedure of the heat treatment efficiency, by only measuring the color – a feature that is both convenient and cost-effective. 

Effects of Heat-Treatment Temperature on the Properties of Negative CTE Eucryptite Ceramics

2010 ◽  
Vol 105-106 ◽  
pp. 123-125 ◽  
Author(s):  
Yong Li ◽  
Qi Hong Wei ◽  
Ling Li ◽  
Chong Hai Wang ◽  
Xiao Li Zhang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Heat Treatment Temperature ◽  
Bending Strength ◽  
Sol Gel ◽  
Negative Thermal Expansion ◽  
Treatment Temperature ◽  
Heat Treated

In this paper, negative thermal expansion coefficient eucryptite powders were prepared by sol-gel method using silica-sol as starting material. The raw blocks were obtained by dry pressing process after the powder was synthesized, and then the raw blocks were heat-treated at 600º, 1150º, 1280º, 1380º, 1420º and 1450°C, respectively. Variations of density, porosity and thermal expansion coefficient at different heat treatment temperatures were investigated. Phase transformation and fracture surface morphology of eucryptite heat-treated at different temperatures, respectively, were observed by XRD and SEM. The results indicate that, with the increasing heat- treatment temperature, the grain size and the bending strength increased, porosity decreased, thermal expansion coefficient decreased continuously. Negative thermal expansion coefficient of -5.3162×10-6~-7.4413×10-6 (0~800°C) was obtained. But when the heat-treatment temperature was more than 1420°C, porosity began to increase, bending strength began to decrease, which were the symbols of over-burning, while the main crystal phase didn’t change.

Sign in / Sign up

Export Citation Format

Share Document