Homogeneous Microstructure Research Articles

Structural and dielectric properties of CaSnO3-doped Sr2.1Na0.8Nb5O15 ceramics

The crystallographic, microstructural, and dielectric properties of Sr2.1Na0.8-xCaxNb5-xSnxO15 (x = 0.00, 0.01, 0.05, 0.10) polycrystalline ceramics have been studied by X-ray diffraction, scanning electron microscopy, dielectric spectroscopy (DS) and impedance spectroscopy (IS). For x = 0.00, 0.05, and 0.10, samples are single phase with P4bm symmetry at room temperature with x = 0.01 showing a small quantity of secondary phase(s). All compositions show typical ceramic microstructures and d50 grain sizes ranging from 5.1 to 26.6 μm. DS shows a clear trend in the high temperature ferroelectric-paraelectric transition with the Curie temperature, T0, decreasing from ∼ 160 to ∼ 110 °C, and an additional relaxation at approximately 120 °C with increasing CaSnO3. IS reveals all samples have a homogeneous electrical microstructure with predominantly electronic conduction. The activation energy of conduction calculated from Arrhenius plots of the conductivity increases with CaSnO3 content from 1.27 to 1.38 eV likely due to the expansion of the band gap.

Discrete model for discontinuous dynamic recrystallisation applied to grain structure evolution inside adiabatic shear bands

Discontinuous dynamic recrystallisation (DDRX) is a well-known phenomenon playing a significant role in the high-temperature processing of metals, including industrial forming and severe plastic deformations. The ongoing discussion on the Zener–Hollomon (Z–H) parameter as a descriptor of materials’ propensity to DDRX and a measure of microstructure homogeneity leaves more questions than answers and prevents its practical application. Most of the existing DDRX models are continuous, and so the geometry and topology of real grain microstructures cannot be considered. The present study uses a fully discrete representation of polycrystalline aluminium alloys as 2D/3D Voronoi space tessellations corresponding to EBSD maps. Such tessellations are geometric realisations of combinatorial structures referred to as polytopal cell complexes. Combining discrete models with FEM LS-Dyna simulations of shock-wave propagation in AA1050 and AW5083 aluminium alloys makes it possible to estimate for the first time the contribution of DDRX to the final material microstructure inside adiabatic shear bands. It is shown that the increase of the initial fraction of high-angle grain boundaries, caused by preliminary deformation, significantly increases the spatial homogeneity and decreases the clustering of DDRX grains. The obtained results contradict the conventional assumption that the microstructures obtained by severe plastic deformation under quasi-static and dynamic deformation conditions are similar due to the similar value of the Z–H parameter: competition between the two recrystallisation mechanisms leads to almost unpredictable final grain structures inside share bands that require further comprehensive experimental studies. This agrees with experimental evidence for high material sensitivity to the Z–H parameter.

Microstructure Characterization of Whey Films Using Different Concentrations of Chia Seeds and 35% Sorbitol as Plasticizer

SEM testing was used to evaluate the homogeneity of the film, including pores, cracks, and surface structure, as well as to determine the cross-section and surface structure and the homogeneity of the film solution mixture. The study aims to determine the microstructure characteristics of whey film by adding different concentrations of chia seed and 35% sorbitol as a plasticizer. This study employed three treatments: P1 with 0.5% chia seed, P2 with 0.75% chia seed, and P3 with 1% chia seed. The research method used was descriptive, providing a detailed description of the process. The results indicate that adding more polymer increases the viscosity of the film suspension during the gelatinization process. The film's microstructure was determined by the heating and drying process, as well as the contribution of chia seed gel to the whey film structure. All treatments achieved a Homogeneous film microstructure, but the 1% concentration treatment resulted in a swollen surface structure. The chia seed was evenly mixed into the whey protein matrix, resulting in a uniform structure.

Structural and ionic conduction study of Sm–Pr co-doped ceria electrolyte materials for LT-SOFC applications

Samarium praseodymium (Sm–Pr) co-doped ceria was synthesized by the co-precipitation technique as an electrolyte for low-temperature solid oxide fuel cell (LT-SOFC) applications. The structural, morphological, compositional, and electrical characterization of the synthesized samples were evaluated via x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX) and impedance spectroscopy. The generation of a single-phase fluorite structure of co-doped ceria without any secondary phases has been verified by XRD analysis, exhibiting the successful incorporation of Sm and Pr ions into the ceria lattice. Vegard's law is utilized for Pr redox behavior explaining the variation in lattice constant values. SEM pictures show that the co-doped ceria powder has a homogeneous and well-dispersed microstructure, and has enhanced particle size. The impedance spectroscopy results indicate that Sm–Pr co-doped ceria has much higher ionic conductivity than single-doped ceria. The highest amount of ionic conductivity (σionic) for the composition Ce0.80Sm0.10Pr0.10O2−δ recorded as 2.12×10−2S/cm at 500°C, and 6.19×10−2S/cm at 750°C with the lowest activation energy Ea=0.48eV, which has been not reported earlier. Sm and Pr are chosen as dopants because of their capacity to generate oxygen vacancies and improve ceria's ionic conductivity. This study contributes to the enhancement in the ionic conductivity of co-doped ceria by co-precipitation technique and the temperature-dependent frequency exponent factor "s" is also explored to comprehend the conduction mechanism of the prepared samples.

Structural and compositional gradients in alternating current sintered aluminum-doped zinc oxide

Flash sintering revitalizes the exploration of electric field and current effects on the microstructure with novel phenomena including rapid densification, low-temperature sintering, and unique microstructures. The aim of this study is to investigate the influence of electric current on the microstructural development of Al-doped ZnO (nAl=4at.%). We apply two sintering techniques, namely spark plasma sintering (SPS) and flash spark plasma sintering (FSPS), both conducted under identical conditions (AC, f=50Hz, |E→0|=25V/cm, p=180MPa) for three different temperatures 600∘C, 800∘C and 1000∘C. The distinguishing factor between the two techniques lies in the passage of electric current flow through the specimens in the case of FSPS. The resulting microstructures of the sintered pellets are examined by XRD, SEM, EDX, TEM and SAED to identify the process-related differences. While SPS specimens reveal a homogeneous microstructure, FSPS specimens exhibit a complex microstructure which consists of two distinct regions. The major volume of the FSPS pellets exhibits a structural gradient with coarse ZnO grains and ZnAl2O4 spinel precipitates in the center to fine ZnO grains at the periphery. This microstructure results from Joule heating and geometry-dependent heat dissipation, creating a symmetric temperature profile with a hot center. A minor volume of the FSPS specimens shows a gradient in microstructure and composition. Here, ZnAl2O4 spinel precipitates accumulate in the center and the periphery reveals Al-depleted, dense and very coarse grains. Electromigration of Al-cations and the thermodynamically favored formation of ZnAl2O4 in the hot center are proposed as underlying causes for the observed microstructure. The electric current in FSPS significantly alters the microstructure and composition of sintered specimen where dopant electromigration is most significant under high current densities above |J→|=29(5)A/cm2.

Processing of High Interstitial Austenitic Steel with Powder Bed Fusion‐Laser Beam/Metal: Evolution of Chemical Inhomogeneity and Microstructural Features during Postprocessing

Powder bed fusion‐laser beam/metal (PBF‐LB/M) additive manufacturing provides a high potential to overcome the poor machinability of nickel‐free high interstitial alloy austenitic (HIA) steels. Therefore, this study focuses on the PBF‐LB/M processability of HIA X40MnCrMoN21‐18‐2 and the effect of postprocessing on microstructure and chemical homogeneity. Samples are fabricated on a laboratory and industrial PBF‐LB/M machine and subsequently postprocessed by conventional solution annealing or hot isostatic pressing (HIP). The influence of the processing steps on the microstructure and on the chemical composition is evaluated by scanning electron microscopy, X‐ray diffraction, transmission electron microscopy, atom probe tomography, and electron backscatter diffraction. The commercially available HIA powder exerts good processability, both by optimized and predefined PBF‐LB/M parameters. Loss of Mn and N is detected after PBF‐LB/M processing. Chemical homogenization but no further change in composition occurs during postprocessing. The as‐built microstructure shows segregation of elements (N, Mo, Cr, Mn) in intercellular spaces. A thermodynamic calculation confirms that N approaches a para‐equilibrium state in the PBF‐LB/M as‐built condition, while C does not. Porosity can be reduced by thermomechanical posttreatment with HIP. At the same time, HIP partially recrystallizes the microstructure, while (Mn + Cr)2SiO4 type oxides delay recovery and recrystallization of the microstructure.

Influence of doping concentrations on the structural, optical, and magnetic properties of Ba-doped LaCoO3 nanostructure

Abstract In this article we report the structural, morphology, vibrational, optical and magnetic properties of Ba x La1−x CoO3 (x = 0, 0.05, and 0.1) (LBCO) samples. The X-ray diffraction shows that samples are in single rhombohedral phase. The Raman signals of LCO were quite small in comparison to LBCO, which exhibited a Raman peak above 675 cm−1. The band seen with a wavenumber of 484 cm−1 corresponds to the vibrational modes of E g bending and Ba–O stretching. UV–DRS and photoluminescence spectra indicated broad absorption over the ultraviolet, visible, and near-infrared spectrums. Surface morphology and EDAX spectra corroborated the materials homogeneous size distribution and homogenous microstructure, with Ba indicating a more stable structure. XPS was used to study chemical states of LBCO and found Co (2p), La (3d), O (1s), and C (1s) elements in perovskite compounds. A peak beneath 300 eV indicated adventitious carbon on surface materials. XPS survey spectrum elements La, Ba, Co, and O had their own binding energies. The magnetization-field dependency of LBCO at 300 K showed that Ba insertion into the LCO switched it from paramagnetic to weak ferromagnetic. Ba considerably decreased magnetic saturation and coercivity, influencing magneto-crystallites’ anisotropy and coercive field.

Studying the Effect of Different Lubricant Materials on the Tribological Properties & Hardness of Cu-Fe Composite Prepared By PM

In this work, three Cu-Fe composite samples are prepared by powder metallurgy technique. This alloy has a superior mechanical property makes it suitable for different engineering applications. The first sample, is the Cu-Fe reinforced with Pb, Sn, Si, Al, Zn and graphite as a lubricant material. The second sample is the Cu- Fe reinforced with only Pb, Sn & 10% BaSO4 which is another type of lubricants, the reinforcements of the third one is 7% BaSO4 with 1% CaCO3 & 5%SiC. All the three samples are prepared by mechanical alloying by 6 :1 ball to powder ratio & 300 rpm for 6 hrs milling time. Then, the mixed composite powders were compacted under 700 Mpa by a uniaxial press and sintered in a vacuum furnace at 950◦C for 90 min. Density and EDAX analysis were examined. The hardness, wear resistance & COF also estimated. The results indicated that sample contains 10% BaSO4 has the highest density & hardness with a homogenous microstructure & the lowest COF. While, the wear rate is the lowest for samples 1&3.

Energy-storage performance of NaNbO3-based ceramic capacitor derived from a high DOP glass network structure

0.75(0.4Na2O-0.1K2O-0.5Nb2O5)-0.25(0.87SiO2-0.13BaO) glass-ceramics were prepared by a traditional melting method to optimize the crystallization kinetics. We obtained a glass network with high degree of polymerization (DOP) by crystallization at different temperatures and achieved a high energy storage density. The increase of crystallization temperature has promoted the precipitation of ferroelectric phases Na0.9K0.1NbO3 and NaNbO3 with high dielectric constant (1200–2000), promoted the increases of grain size from 0.76 μm to 1.33 μm, and reduced the gap width from 3.71eV to 3.22eV. When the crystallization temperature increased to 1000°C–1100 °C, Ba2NaNb5O15 with low dielectric constant (∼460) increases, grain boundaries appear, and dielectric constant and BDS decrease. Among all the samples, the sample crystallized at 900 °C showed homogeneous and dense microstructure (grain size∼0.91 μm). The experimental data confirmed that the glass sample crystallized at 900 °C achieves low dielectric loss (<0.005) and high dielectric constant (∼122). The glass sample crystallized at 900 °C sample had a maximum energy storage density of 3.65 J/cm3, a power density of about 54 MW/cm3 and a super-fast discharge speed of 38 ns at 660 kV/cm.

Systematic evaluation of the radial polarized piezoelectric ceramic micro-tube for high-temperature microfluidics

Piezoelectric ceramic micro-tube (PCMT) featuring quick response and driving displacement resolution has been widely applied in the microfluidic field. With more and more microfluidic applications being conducted in high temperatures, there is an increased demand for high-temperature PCMTs. However, few reports were focused on evaluating the performance of PCMTs especially in high-temperature conditions, which hinders its applications greatly. In this paper, a radial polarized high-temperature PCMT with an inner diameter (ID) of 0.75 mm, an outer diameter (OD) of 1.2 mm and a length of 15 mm was fabricated first. Scanning electron microscope (SEM) test shows that this ceramic tube presents a homogenous and dense microstructure. Impedance spectrum tests at different temperatures show that the effective electromechanical coupling factor (keff) of this PCMT remains stable from room temperature to 250 °C, indicating good high-temperature stability. Quasi-steady axial displacement tests executed by the instrument constructed by our group show that this PCMT represents a linear driving response under 100 V. Based on systematic evaluations, the PCMT was used to fabricate a piezoelectric high-temperature nozzle for generating high-frequency droplets, through which tin droplet targets with a repetition frequency of 20 kHz and a diameter of 100 μm was obtained at 250 °C. The successful application demonstrates that the PCMT which was evaluated systematically can be used in practical high-temperature applications.

Effect of ultrasound assistance on the mechanical performance and corrosion resistance of Zn-Ni coatings produced by cathode plasma electrolysis deposition

Zn-Ni coatings were fabricated via ultrasonic-assisted cathodic plasma electrolysis deposition (US-CPED) technology. The results demonstrate that ultrasonic assistance can significantly affect the deposition and growth process of Zn-Ni coatings, which is attributed to ultrasonic vibration reducing the diameter of bubbles and inducing a more uniform distribution of the vapor gaseous envelope (VGE) on the surface of the substrate. The Zn-Ni coatings with more homogeneous microstructure were formed due to the more uniform plasma discharge process on the surface of the substrate based on the VGE uniform distribution. Compared to the Zn-Ni coatings without ultrasonic assistance, the thickness and roughness of Zn-Ni coatings with ultrasonic assistance increased by >80 % and decreased by over 40 %, respectively. Better Zn-Ni coating quality brings higher corrosion resistance. In addition, ultrasound can accelerate the iteration of bubbles in VGE to enhance the work-hardening effect, improving the mechanical properties of the Zn-Ni coatings. This work introduces a novel insight into the controllability of the CPED process and paves the way for exploring other methods to stabilize the CPED process.

Compressive strength development and microstructure evolution of mortars prepared using reactivated cementitious materials under carbonation curing

The effect of carbonation curing on depth-wise carbonation gradient and compressive strength development of RCM was evaluated. The RCM mortars were carbonated for seven curing periods, complemented by a thorough investigation of carbonation degree, phase assemblage, and microstructural at varying depths. Results showed a significant increase in compressive strength, from 3.3 MPa on the first day to 51.7 MPa after seven days and 63.5 MPa after 28 days of carbonation curing. A notable gradient in CaCO3 concentration was observed, decreasing from 41.4% at the surface to 16.8% at 25 mm depths. Additionally, the formation of CaCO3 polymorphs and Ca-modified silica gel in the surface layers was found to enhance microstructural density and impede CO2 penetration, while a higher prevalence of micropores was noted in the inner regions. These findings highlight the potential of optimizing the carbonation regime or employing internal carbonation methods to achieve a more homogeneous microstructure.

In-situ monitoring of additive friction stir deposition of AA6061: Effect of layer thickness on the microstructure and mechanical properties

Depositions of AA6061 aluminum alloy with different thicknesses (0.5, 1.0 and 1.5 mm) and homogeneous microstructure were successfully obtained through additive friction stir deposition (AFSD) technique. A self-developed in-situ process monitoring kit has been utilized to in-situ monitor the real-time temperature, force and torque during the AFSD process. Effect of thickness on the microstructure and mechanical properties are investigated based on the monitored parameters. With the electron back scattered diffraction (EBSD) analysis on a large area (4 × 4 mm2), the synergism of dynamic recrystallization (DRX) and shear deformation is found to affect the microstructure. DRX is the main reason for the grains refinement which are remarkably reduced to 7 μm as the thickness increases. Whereas, the shear deformation exhibits a stronger effect on the texture. The texture intensity reduces and then increases as the thickness increases from 0.5 to 1.5 mm. Values of micro-hardness (46.8 HV0.5), yield strength (106.0 MPa) and ultimate tensile strength (171.2 MPa) of the deposition are the highest when the thickness is the largest (1.5 mm) attributed to the lowest thermal cycle and evolution of DRX. All the findings provide useful guidance for the visualization and understanding of AFSD process.

Feature similarity gradients detect alterations in the neonatal cortex associated with preterm birth.

The early life environment programmes cortical architecture and cognition across the life course. A measure of cortical organisation that integrates information from multimodal MRI and is unbound by arbitrary parcellations has proven elusive, which hampers efforts to uncover the perinatal origins of cortical health. Here, we use the Vogt-Bailey index to provide a fine-grained description of regional homogeneities and sharp variations in cortical microstructure based on feature gradients, and we investigate the impact of being born preterm on cortical development at term-equivalent age. Compared with term-born controls, preterm infants have a homogeneous microstructure in temporal and occipital lobes, and the medial parietal, cingulate, and frontal cortices, compared with term infants. These observations replicated across two independent datasets and were robust to differences that remain in the data after matching samples and alignment of processing and quality control strategies. We conclude that cortical microstructural architecture is altered in preterm infants in a spatially distributed rather than localised fashion.

Effects of extrusion die cavity on the texture components and the associated mechanical properties for ZK60 magnesium alloy

This work managed the extrusion strain path by designing various extrusion die cavities, successfully realizing the texture modification for the ZK60 magnesium alloy. The mechanisms involving the texture dependence on the extrusion die cavity as well as their effects on the mechanical properties were emphatically investigated. Results showed that dynamic recrystallization refined the grain size and improved the microstructure homogeneity in the three extrusion specimens, but did not produce too large microstructure differences. By comparison, significant texture differences developed owing to the various extrusion die cavities, which here were mainly reflected in the strong or weak texture components for the c-axes//TD and the c-axes//ND. Such texture differences started from the deformation texture instead of the recrystallization texture whose roles only consisted in dispersing the texture component and reducing the texture intensity. The results from the finite element analysis and the visco-plastic self-consistent model indicated that, in order to accommodate the different strain components induced by the extrusion die cavities, slip systems or tension twinning were activated differently, and this was the critical reason causing the above texture differences. One modified Hall-Petch relationship was adopted to analyze the conjoint effects of grain refinement and texture variation on the yield stress. Additionally, the quantitative results about deformation mechanism activation fractions demonstrated that the texture variations influenced the competition relationships between the twinning induced deformation and the slip dominant deformation, and the former generally produced the lower yield stress and the increasing stage of strain hardening rate, while the latter produced the higher yield stress and the continuous decline of strain hardening rate.

Effect of cryorolling on microstructure evolution and mechanical properties of spray deposited Cu-Fe alloy

In order to solve or suppress the problem of macro segregation of Fe phase of Cu-Fe alloy in the traditional casting process, we successfully prepared Cu-10Fe alloy prefabricated slabs with homogeneous and fine microstructure by spray deposition and achieved high strength Cu-10Fe alloy thin strips by subsequent cryorolling. Cryorolling was carried out at different reductions to investigate the relationship between microstructure evolution and mechanical properties. The results show that the spray deposited alloys have good plasticity and low temperature workability. As the reduction increased, the Fe phase becomes more fibrous and the average grain size of the alloy is refined to 0.35 μm. The {112}<111> texture was gradually transformed into a stabilized {110}<112> texture during cryorolling suggested that the low temperature suppressed cross-slip and improved the strength of the alloy. The mechanical properties of the alloys improved significantly after cryorolling is mainly attributed to the significant grain refinement, dislocation accumulation and the presence of ultrafine grains during the cryorolling process. The successful development of thin strips of Cu-Fe alloy with uniform distribution of Fe phase and high strength provides a new idea for the preparation of thin strips of immiscible alloys such as Cu-Fe alloy.

Influence of Grain-Growth Inhibitors on Modified (Ba,Sr)(Sn,Ti)O3 for Electrocaloric Application.

The paper reports on effect of grain-growth inhibitors MgO, Y2O3 and MnCO3 as well as Ca modification on the microstructure, dielectric, ferroelectric and electrocaloric (EC) properties of Ba0.82Sr0.18Sn0.065Ti0.935O3 (BSSnT). Furthermore, the effects of the sintering time and temperature on the microstructure and the electrical properties of the most promising material system Ba0.62Ca0.20Sr0.18Sn0.065Ti0.935O3 (BCSSnT-20) are investigated. Additions of MgO (xMgO = 1%), Y2O3 (xY2O3 = 0.25%) and MnCO3 (xMnCO3 = 1%) significantly decreased the mean grain size of BSSnT to 0.4 µm, 0.8 µm and 0.4 µm, respectively. Ba0.62Ca0.20Sr0.18Sn0.065Ti0.935O3 (BCSSnT-20) gained a homogeneous fine-grained microstructure with an average grain size of 1.5 µm, leading to a maximum electrocaloric temperature change |ΔTEC| of 0.49 K at 40 °C with a broad peak of |ΔTEC| > 0.33 K in the temperature range from 10 °C to 75 °C under an electric field change of 5 V µm-1. By increasing the sintering temperature of BCSSnT-20 from 1350 °C to 1425 °C, the grain size increased from 1.5 µm to 7.3 µm and the maximum electrocaloric temperature change |ΔTEC| increased from 0.15 K at 35 °C to 0.37 K at 20 °C under an electric field change of 2 V µm-1. Our results show that under all investigated material systems, BCSSnT-20 is the most promising candidate for future application in multilayer ceramic (MLC) components for EC cooling devices.

Pt-modification on the thermal cycling behavior of NiCoCrAlYTa coating: A case study

A NiCoCrAlYTa coating possessing homogenous microstructure was fabricated by high velocity oxygen fuel (HVOF) technique, in which some of the coating samples were electroplated with a thin layer of Pt. After vacuum annealing, thermal cycling tests of the NiCoCrAlYTa coatings with and without Pt modification were carried out at 1050 °C till 1000 cycles. The results revealed that Pt modification has assisted to improve the stability of the coating and to develop a highly purified alumina scale, where lower oxidation rate and residual stress were achieved in the Pt-modified NiCoCrAlYTa coating.

Hot Deformation Behavior of a Hot-Isostatically Pressed Ti-6Al-4V Alloy from Recycled Powder.

In this work, a new use of mixed Ti-6Al-4V powder, consisting of the retained powder after screening for additive manufacturing and the recycled powder after multiple printing, has been exploited. The powder mixture has been hot-isostatically-pressed (HIPed) at 930 °C/120 MPa for 3 h to reach full density. The hot deformation behavior of the as-HIPed powder compacts were investigated through isothermal compression tests, kinetic analyses, and hot processing maps. Finally, the optimized hot working parameters were validated using upsetting tests. The results show that the as-HIPed Ti-6Al-4V alloy has a fine and homogeneous microstructure. The activation energies were calculated to be 359 kJ/mol in the α + β phase regime and 463 kJ/mol in the β phase regime, respectively. The optimal hot working parameters are a deformation temperature above 950 °C and strain rate higher than 0.1 s-1. The hot workability of as-HIPed powder compacts is better than the as-cast billets. The deformed microstructure can be finer than that of as-HIPed state, and the mechanical performance can be further improved by the optimal thermo-mechanical processing treatment.

PENGARUH PENAMBAHAN PROSES INOKULASI TERHADAP STRUKTUR MIKRO DAN KEKERASAN PRODUK COR DENGAN MATERIAL FC 250

The inoculation process in metal casting is needed to make grey cast iron or nodular cast iron. Inoculation aims to increase the number of freezing nuclei and promotes the formation of a homogeneous microstructure. This research aims to determine the effect of the inoculation addition process on the microstructure and hardness of PP products with FC-250 material. The changes made include changes to the inoculation process and changes to the chemical composition of the induction furnace. Changes in the inoculation process include changing the inoculation process which was initially only carried out on ladles with an inoculation material weight of 0.5 kg to 2 processes, namely on ladles with an additional weight of 0.8 kg of inoculation material and an inoculation process on crucible (kowi) with an additional material weight of 0.4 kg. The results of the metallography test after the additional inoculation process showed that the pearlite and ferrite graphite spread evenly and fell into Type-A graphite. The hardness test results show that the effect of adding inoculation changes the level of hardness so that it complies with ASTM 40 specifications/standards, namely 180 – 302 HB. The hardness value after the addition of the inoculation process was 190 HB.