Near-infrared Reflective Diffusion Coating Is Beneficial for Asparagus Summer Production in a Simple Plastic Greenhouse

Asparagus is a potential greenhouse crop, and its production is considerably affected by temperature and light, especially in the summer season. This study investigated the effects of the application of near-infrared (NIR)-reflective diffusion coating on a simple plastic greenhouse on microclimatic conditions, plant response, spear yield, and quality of the asparagus plant in central Taiwan. The results showed that NIR-reflective diffusion coating reduced the mean air temperature inside the greenhouse by 0.3 to 0.9 °C and leaf temperature by 2.3, 2.4, and 2.4 °C at a canopy height of 50, 100, and 50 cm, respectively. Although the accumulated daily light integral (DLI) transmitted in the coated greenhouse exhibited an 18.9% reduction compared with a 16.8% reduction in the noncoated greenhouse, a more uniform spatial light distribution was noted. Therefore, photosynthesis improved in the middle and bottom canopy, and plants could maintain a higher transpiration rate, thus resulting in atmospheric cooling. The average spear yield increased by 31.4% in summer and by 10.1% during the following harvest with a lower crude fiber (CF) content and higher Ca as well as Mg contents. In addition, the number of newly emerged shoots increased by 48.8% after the removal of the mother stalk under coating. NIR-reflective diffusion coating can be used as an energy-saving method for enhancing cooling and improving light use efficiency, thus increasing asparagus production in a greenhouse in summer.

Quality assessment of AL-C-B coatings on steel surfaces obtained by electro spark alloying

Problem. As a rule, during the operation of the product, the surface layers of materials are most affected. These can be parts that work in aggressive environments, at high temperatures, various force actions, the presence of abrasive particles, etc. Under such conditions, different types of steels and alloys are used, and, most commonly, it is high-alloy, which significantly complicates the manufacturing process and increases the cost of the finished product. Diffusion coating methods are the most widespread in the industry, which is due to the best study and ease of these processes. However, there are alternative methods of surface treatment, which are devoid of the disadvantages of diffusion methods. The goal is to develop a method of obtaining boron-containing coatings of the Al-C-B system by the electro spark alloying (ESA), applying STS to the treated surface, to study the processes of structural and phase formation of surface layers depending on the energy processes of ESA and substrate material. Methology. Samples made of steel 20 and 40 were used for the study, on which a coating consisting of their sulfur ointment, aluminum powder, amorphous boron powder was applied. Without waiting for drying, the ESA surfaces of the samples were carried out with a graphite electrode on an installation with a discharge energy of 0.13, 0.55 and 4.9 J. The surface roughness after treatment was determined on a profilograph-profilometer by removing and processing profilograms. Metallographic analysis of coatings was performed using an MIM-7optical microscope, and durometric studies were made on the PMT-3 device according to standard methods. Results: the article presents the original method for obtaining boron-containing coatings of the Al-C-B system by the ESA method, which involves applying a coating consisting of sulfur ointment, aluminum powder, amorphous boron powder on the treated surface, followed by electric spark doping with a graphite electrode.

Kinetics of the formation of a diffusion layer on AISI 1045 steel with simultaneous saturation with boron, chromium and titanium

Research has been carried out to determine the kinetics of coating formation on AISI 1045 steel with diffusion saturation with boron, chromium and titanium simultaneously. It was found that the experimental parameters of the thickness of the diffusion layer of borides over time outstrip the calculated values. The diffusion layer has a thickness of 120 μm with a saturation duration of 2.5 h, 155 μm with a saturation duration of 5 h, and 180 μm with a saturation duration of 7.5 h. In addition to studying the kinetics of the formation of a diffusion coating, also studied the distribution of microhardness over the cross section of the diffusion coating. The maximum microhardness of the diffusion coating is observed not on the surface, but at some distance from it. On average, at a depth of 45–60 µm from the surface. In this case, the microhardness on the surface of the diffusion coating, on the contrary, tends to take on a minimum value of about 1800 HV0.1. Such a distribution of microhardness it gives the parts the possibility of minor surface wear.

Formation of the Diffusion Zone in Explosion Welded Composite Cr20Ni80 - AD1 at Liquid-Phase Interaction

The paper presents the investigation on the structure, chemical and phase composition of the diffusion coating formed during the liquid-phase heat treatment in the explosion-welded Cr20Ni80 + AD1 bimetal. It is shown that the coating structure consists of NiAl3, CrAl7, Ni2Al3 intermetallic inclusions, as well as a metastable ternary compound – τ2-phase (Al77.5Cr12.5Ni10) of different dispersion and morphology. There are no crystallization defects in the coating structure.

Research of chromosilicated coatings on compact powder steels

Microstructures, chemical and phase compositions of diffusion chromosilicated coatings on powder steels 20, 45, У8 and У10 are investigated. The presence of Cr23C6 and Cr7C3 phases with up to 0,25 % Si is shown in these coatings. The distribution of diffusing chemical elements over the depth of the coating and at the interface with the matrix base is studied. Keywords: diffusion, coating, microstructure, chromosilication, powder steel, corrosion resistance [email protected]

FORMATION OF THE STRUCTURE AND COMPOSITION OF THE DIFFUSION INTERACTION ZONE DURING THE HEAT TREATMENT OF THE EXPLOSION-WELDED AD1 + Cr20Ni80 COMPOSITE IN THE PRESENCE OF A LIQUID PHASE

The paper presents the study results of the structure, chemical and phase composition of the diffusion coating formed during the heat treatment of the explosion-welded Cr20Ni80 + AD1 bimetal according to the regime providing liquid-phase interaction (above the melting point of aluminum) on the surface of the Cr20Ni80 alloy. It is shown that its structure consists of inclusions of NiAl, CrAl, NiAl intermetallic compounds, as well as a metastable ternary compound - τ-phase with composition of AlCrNi of different dispersion and morphology. There are no crystallization defects in the coating structure.

THERMODYNAMIC ANALYSIS OF THE GAS MEDIUM IN THE FORMATION OF DIFFUSION COATINGS USING COMPOSITE SATURATING CHARGES

Review of the main processes of formation of diffuse coatings doped with molybdenum,vanadium and tungsten. The basic features of the formation of diffusion layers during chemicalthermaltreatment are considered.: When the SHS is tested, the container is heated to temperaturesof 1173-1330 K. Within 1-2 hours, a diffusion coating is formed due to the saturation of thesurface of structural materials with atoms of saturating elements - Cr, Al, V, Ti, B, W, Mo. Assaturating elements, the defects of these elements and the chemical compounds of these elementswere used, and to determine the possibility of using specific substances, chemical reactionswere considered that can occur in the temperature range of diffusion saturation usingSOS. It should be noted that the metallothermal Reduced oxide, which is used in the synthesisof powder media for CHT, is very fast. When obtaining diffuse layers using the composition ofsaturating the medium, a gas phase is formed, containing spolo-I, I2, I3, H, H2, H3, Cl2, Cl3 withchemical elements. With an increase in temperature, an increase in the amount of halides isobserved. This confirms the possibility of transferring alloying elements for the formation of diffusioncoatings. Also, the amount of products in the gaseous phase increases and condensedproducts are released. It is characteristic that in the temperature range of 700-1500 K, the decompositionof reaction products occurs during CHT, which is confirmed by the production ofdecomposition substances and a sharp increase in the number of gas moles.

NITRO-OXIDATION PRODUCTS FROM STRUCTURAL STEELS

The article examines the technology of nitro-oxidation, which consists of nitriding in separated ammonia at the first organize and oxidation in water vapor at the second stage of the process, studied the structure and phase composition of the diffusion nitride-oxide layer, providing high physico-mechanical and physicochemical surface characteristics, competitively capable of galvanic strategies of getting a coating, the conceivable outcomes of regulating the structure and phase composition of the nitride-oxide layer are being investigated to obtain a diffusion coating composition with predetermined properties.