Heat-treated Films Research Articles

Facile hydrothermal synthesis of Sb2S3 thin-film photo-cathodes for green hydrogen energy production

Semiconducting characteristics of antimony-based chalcogenides in the recent past gained the utmost attention for photovoltaic (PV) cells and photo electrochemical (PEC) hydrogen evolution. In the current research endeavour, a simple hydrothermal route has been employed to prepare polycrystalline Sb2S3 thin films. Under ideal temperature conditions of 120 °C, Sb2S3 films were prepared in an autoclave, varying the reaction times between 10:00 and 14:30 h with an interval of 30 min. Further heat treatment of the as-synthesized Sb2S3 thin films was carried out on an electric hot plate at 200 °C for 90 min. XRD analysis of heat-treated Sb2S3 films unveiled an orthorhombic crystal structure with (310) predominant plane. Consequently, the crystallite sizes, displayed improvement from ∼ 33 to 77 nm, with reaction periods for 10:00 to 13:30 h and decreased after that. The five distinct Raman modes were spotted at 155, 190, 236, 280, and 305 cm−1, further confirming the single-phase formation of Sb2S3 thin films. SEM and EDS analysis indicated conspicuous variations in surface morphology and stoichiometric ratios of antimony and sulfur elements. The Sb2S3 thin films deposited at 120 °C for 13:30 h are found to be nearly stoichiometric (Sb and S are 42.61 and 57.39 at. %). The resultant oxidation states were demonstrated to be (+3) and (−2) for antimony and sulfur respectively. All the thin films exhibited an optical absorption coefficient greater than 104 cm−1 with a direct energy band gap ranging between 1.43 and 1.61 eV. The Sb2S3 thin films deposited for 13:30 h have unveiled the highest photocurrent density of −0.27 mA/cm2, indicating a potential photocathode for hydrogen production.

Physicochemical and structural properties of silica films prepared from perhydropolysilazane using vacuum ultraviolet irradiation

Developing techniques to form functional films at low temperatures is crucial for enabling their application on materials with limited heat resistance. In this study, silica films were prepared by irradiating a perhydropolysilazane (PHPS) precursor, which contains reactive Si–H and N–H groups and is free from organics, with vacuum ultraviolet (VUV) light under a controlled atmosphere. To investigate the quality of the resulting films and mechanisms behind photochemical conversion, infrared and electron spectroscopic measurements were performed. The results revealed that VUV irradiation converted the top surface of the film into silica, irrespective of the atmospheric conditions. However, differences in the oxygen concentration affected both the VUV light intensity penetrating the film and the oxygen diffusion into it, leading to the formation of silica or silicon oxynitride within the film. Under irradiation, PHPS was converted to silica not only from the surface but also from the interface with the substrate. In addition, silica was formed even at long irradiation distances, in which case VUV light barely reached the PHPS surface owing to absorption by atmospheric oxygen. These findings demonstrate that the silica-film formation involved two processes: breaking of chemical bonds induced by VUV photons and oxidation due to oxygen diffusion from the surface. The spectroscopic measurements and X-ray reflectivity results indicated that the composition, chemical state, Auger parameter, and density of the prepared silica film were comparable to those of a silica film prepared through heat treatment at 500°C. Further, the prepared silica film using VUV irradiation had a smoother surface than that of the heat-treated film. The thickness of the prepared film remained unchanged before and after VUV irradiation, indicating that the formation process using VUV irradiation suppressed the shrinkage of the film during the conversion of PHPS to silica.

In vitro Biomineralization Ability of Magnesium-Doped Coral Hydroxyapatite Coating Prepared by Pulsed Laser Deposition

Coral hydroxyapatite (CHA) is a calcium phosphate that has a similar inorganic composition to human bone and the porous structure of coral stone. Due to its interconnected network like pore structure, it can serve as a framework for bone conduction. In this study, CHA films and Mg-CHA films were deposited on titanium and silicon substrates by Pulsed laser deposition, and then the films were heat treated respectively. Studies on the adhesion of the coating showed that the heat-treated Mg-CHA film adhered better to the titanium substrate. The experimental study on biomineralization in vitro showed that a small amount of porous structure appeared in the heat-treated Mg-CHA after immersion in SBF for three days, and the porous structure was visible after immersion for seven days. After 14 days, a new apatite layer formed on the surface. This suggested that magnesium undergoes chemical corrosion in SBF, leading to rapid ion exchange, which results in the formation of porous structures and promotes the development of an apatite-like layer. In summary, the heat-treated Mg-CHA films had superior biomineralization properties.

High stability and photocatalytic activity of N-doped ZrO2 thin films

Undoped and nitrogen-doped ZrO2 thin films were obtained by HiPIMS on ITO/glass substrates. To stabilize their structure, the films were subjected to a heat treatment. The properties of the heat-treated films (structure, morphology, elemental composition of the atomic species at the films surface, optical band gap, wettability and oxidation performance of Rhodamine B) were correlated. Some properties of the studied films were compared with the ones of the as-deposited films previously reported. By nitrogen doping, zirconia thin film modifies its fundamental absorption edge, becoming absorbent in the visible domain. The heat treatment improves the hydrophilic properties of both undoped and N-doped films, the last one becoming super-hydrophilic. The photocatalytic activity under UV was investigated for three RhB concentrations. The degradation efficiency is higher than 90 % for both undoped and N-doped ZrO2 films, being better for the N-doped film. The studied films are exceptionally stable, keeping their oxidation properties almost unchanged after five degradation cycles, with a special remark for the N-doped film (the degradation efficiency around 93 %). The role of ITO substrate in charge carriers separation was investigated, based on the allowed band edges values, determined both for the films and ITO.

Structure and physical properties of multicomponent films based on the Fe-Si-B system

The influence of modernized three-electrode ion-plasma sputtering of a complex Fe–Si–B– (Cu, Nb)/(Ni, Mo) target on the structure and properties of sputtered films was studied. The formation of amorphous and nanocrystalline phases in Fe73Si15.8B7.2-(Cu, Nb)4 and Fe78.5Si6B14-(Ni, Mo)1.5 films with a coherent scattering region size of 1.6 nm and 12 nm, respectively, was established as a result of a modernized three-electrode ion - plasma sputtering. The thermal stability of metastable states of films as well as electrical and magnetic properties of freshly prepared and heat-treated films has been investigated. The conditions for obtaining films with low values of the temperature coefficient of electrical resistance (−0.9∙10−5 K−1) and coercive force (HC ∼11 A/m) have been determined.

FeCuNbSiB thin films with sub-Oersted coercivity

We investigated the microstructural and magnetic properties of nanocrystalline FeCuNbSiB thin films produced through magnetron sputtering followed by heat treatment. Our research focused on film thicknesses (80 nm and 160 nm) and heat treatment temperatures (490 °C–520 °C) that resulted in samples characterized by low coercivity and high effective magnetization. Conducting a comprehensive microstructural examination, we employed X-ray diffraction and transmission electron microscopy techniques, including selected area electron diffraction, high-resolution imaging and Fourier transform analysis. Magnetic properties were investigated using an alternating gradient field magnetometer and broadband ferromagnetic resonance. Structural analysis revealed, for all our heat-treated films, a well-defined microstructure characterized by nanograins, with a Fe3Si ferromagnetic phase, embedded within an amorphous matrix. Our films exhibit sub-Oe coercivity, reaching as low as 0.51 Oe, along with an increase in effective magnetization from 1170 emu/cm3 for the amorphous phase to a maximum of 1260 emu/cm3 in the nanocrystalline phase.

Effects of thermal treatment on the electrical behavior of titanium dioxide thin-films

AbstractElectrochemical biosensors made of titanium dioxide have generated significant interest due to their high sensitivity and selectivity for the detection of a variety of diseases. This study focuses on the impact of thermal treatment in an oxygen environment on the electrical properties of titanium dioxide thin films deposited on silicon substrates using pulsed laser deposition; the films were subjected to temperatures of $$\varvec{100\,\,^{\circ }C}$$ 100 ∘ C , $$\varvec{400\,\,^{\circ }C}$$ 400 ∘ C , and $$\varvec{600\,\,^{\circ }C}$$ 600 ∘ C . The primary objective was to explore how thermal processing influences the electrical characteristics of the thin films, with the goal of enhancing their capacitance and thereby improving the performance of sensors developed by functionalizing these films; X-ray photoelectron spectroscopy revealed the presence of Ti$$^{4+}$$ 4 + , Ti$$^{3+}$$ 3 + and TiO$$_x$$ x species in the untreated thin film and in the heat-treated films, with an increase in TiO$$_x$$ x species observed after oxygen heat treatment. Atomic force microscopy demonstrated a decrease in the surface homogeneity of the films at elevated treatment temperatures, which corresponded to a reduction in capacitive behavior; this was further corroborated by Nyquist plots derived from electrochemical capacitance spectroscopy (ECS). The study found that the electrochemical capacitance at lower frequencies decreased significantly from $$\varvec{1.02\,\, \mu Fcm^{-2}}$$ 1.02 μ F c m - 2 to $$\varvec{0.25\,\, \mu Fcm^{-2}}$$ 0.25 μ F c m - 2 when the treatment temperature was increased to $$\varvec{600\,\,^{\circ }C}$$ 600 ∘ C

Ensuing the formation of photocatalytic TiO2/Fe2O3 nanocomposite from heat treatment of electrophoretically deposited TiO2 films on stainless steel

In this study, thermal transformations in electrophoreticlly coated TiO2 coatings on SS-316L substrate were investigated. Such films were previously employed for antibcaterial purposes, however their heat-treatment at 900 °C resulted in an unexpected transformation in the film color. This study was designed to trace back the origin of such optical transformation in the TiO2 film that was expected to be whitish in its outlook, however it became brownish at elevated temperature, indicating an exploitable characteristics of visible light absorbance. The films were carefully transformed to particles by subsequently applying scratching/ball milling method and characterized through various materials’ characterization tools including but not limited to SEM-(EDS), XRD, alongside characteristic characterizations such as TGA, UV-Vis and EIS for elucidating thermal, optical and electrochemical behavior respectively of particles obtained from pristine (TiO2) and heat-treated films (termed as TFNC) owing to the transformation of TiO2 to TNFC (i.e. TiO2/Fe2O3) nanocomposite. TFNC exhibited decreased band gap from 3.2 eV to 2.86 eV and consequently improved photocatalytic activity. The TFNC degraded 50% Rhodamine B dye under visible light, while pure TiO2 degraded only 13%, which was credited to the formation of Fe2O3 particles inside TiO2 film. It was estimated that the Fe-element was capable to diffuse inside such TiO2 film and resulted the formation of TFNC at ≥ 900°C. The evolution of visible light dependent photocatalytic performance in TFNC was credited to the lowering of bandgap and enhanced electron-hole generation as investigated by EIS.

Production of Babbitt Metal Thin Film by Thermal Evaporation Method and Investigation of the Change of Thıs Thin Film With Heat Treatment Time

Babbitt alloy is in high demand thanks to its superior corrosion resistance and its hollow-soft structure. Because of these important features, it has been the subject of many studies. In this study, the thin film state of Babbitt alloy will be examined. For this purpose, tin (Sn) based Babbitt alloy on the glass substrate was turned into a thin film by thermal evaporation and these thin films were subjected to heat treatment at 120 oC for different times and the heat treatment effect was examined. The crystal structure of non-heat-treated and heat-treated babbitt thin films was determined by x-ray measurement. It was observed that thin films formed as agglomerations on the crystal structure of tin, and it was observed that the crystallization increased as the heat treatment time increased. Grain-grain boundaries are clearly visible on the coating surface from SEM images. It was determined that the grain sizes decreased in proportion to the heat treatments applied to the thin films at different times and the additive ratios. In addition, it was determined from the EDX results that the oxide layer accumulated in the form of bumps on the surface increased depending on the processing time applied to the thin films obtained and that these layers were composed of tin, antimony and oxygen elements. Finally, it was observed from the AFM images that the roughness value on the thin film surface gradually decreased with the increase of the oxide layer deposited on the surface.

Exploring the Influence of the Deposition Parameters on the Properties of NiTi Shape Memory Alloy Films with High Nickel Content

NiTi shape memory alloy films were prepared by magnetron sputtering using a compound NiTi target and varying deposition parameters, such as power density, pressure, and deposition time. To promote crystallization, the films were heat treated at a temperature of 400 °C for 1 h. For the characterization, scanning electron microscopy, energy dispersive X-ray spectroscopy, atomic force microscopy, synchrotron X-ray diffraction, and nanoindentation techniques were used on both as-deposited and heat-treated films. Apart from the morphology and hardness of the as-deposited films that depend on the deposition pressure, the power applied to the target and the deposition pressure did not seem to significantly influence the characteristics of the NiTi films studied. After heat treatment, austenitic (B2) crystalline superelastic films with exceptionally high nickel content (~60 at.%) and vein-line cross-section morphology were produced. The crystallization of the films resulted in an increase in hardness, Young’s modulus, and elastic recovery.

A flexible piezoelectric/pyroelectric dual-function sensor with high temperature resistance

Most of existing piezoelectric polymers have low glass transition temperatures, so they can only operate at lower temperatures (<150 ℃). Once the operating temperature is exceeded, the piezoelectric performance of the device rapidly decreases. At higher temperatures, dense chain motion can interfere with the orientation of dipoles, thus limiting the development of polymer based high-temperature piezoelectric sensors. High-temperature piezoelectric sensor devices are entirely made of inorganic materials, however, inorganic materials are rigid and can only work under small strains. Therefore, enhancing the temperature resistance of piezoelectric polmers and constructing piezoelectric asymmetric structure are the key to fabricating flexible high-temperature resistant piezoelectric/pyroelectric dual functional sensors. In this study, polyacrylonitrile (PAN) nanofiber film is prepared by electrospinning, and then subjected to heat treatment through programmed temperature control. The effects of the different heat-treatment temperatures on the mechanical and electrical performance of PAN nanofiber film are studied systematically, and the results show that PAN high temperature resistant flexible nanofiber film sensors can be used in high temperature environments (> 500 ℃). Its output performance is improved with the increase of heat treatment temperature (< 260 ℃) and then basically remains unchanged in a temperature range of 260–450 ℃. Finally, the output performance decreases at temperatures higher than 450 ℃. When the heat treatment temperature reaches 260 ℃, the output voltage increases to 10.08 V, and current reaches 2.89 μA. Compared with those of the untreated PAN membranes , its output voltage and current are increase by 3.54 times and 2.83 times, respectively. At the same time, the output of the PAN high temperature resistant flexible nanofiber film sensors is almost unchanged in the high-temperature environments. This is the first time that the pyroelectric effect has been observed in heat-treated PAN nanofiber films and both the open-circuit voltage and short-circuit current have been shown to increase with temperature gradient increasing. Besides, the PAN nanofiber film sensors have durability of more than 5000 cycles at room temperature(25 ℃) even at high temperature (400 ℃). Overall, good flexible, high-temperature resistance, and bifunctional sensing ability make PAN flexible nanofiber film sensors expected to be widely used in high temperature environments such as fire safety, aerospace and other harsh environment.

Preparation of Fe-Si-B-(Cu,Nb,Ni,Mo) films by quenching from a vapor state

Using modernized three-electrode ion-plasma sputtering, homogeneous thin films of Fe-Si-B-(Cu, Nb), and Fe-Si-B-(Ni, Mo) were obtained. The structure of the films was investigated by X-ray diffraction and electron microscopy. It was established that as a result of sputtering, amorphous and nanocrystalline phases with a coherent scattering region (CSR) size of 1.6 nm and 12 nm were formed in the Fe73Si16B7-(Cu, Nb)4 and Fe78.5Si6B14-(Ni, Mo)1.5 films. The thermal stability of metastable states of the films, as well as theelectrical and magnetic properties of freshly prepared and heat-treated films were studied. The conditions for obtaining films with small (modulo) values of the temperature coefficient of electrical resistance ( - 0.9∙10-5 K-1) and coercive force (HC ~ 11 A/m) were determined.

Investigation of Optical and Structural Properties of VO2 Thin Films by Thermal Treatment

In this study, VO2 thin films were grown on SiO2 substrate using the PLD method. Then the grown VO2 thin films were subjected to heat treatments at different temperatures and times in the atmosphere environment. The structural properties of the heat-treated films were investigated using X-ray diffraction (XRD) technique and Raman spectroscopy techniques. The surface microstructures of these films were investigated by Scanning Electron Microscope (SEM) technique, and their optical properties and bond structures were investigated by Photoluminescence (PL) spectra and Fourier Transform Infrared Spectroscopy (FTIR) measurements, respectively. Especially XRD and Raman results revealed that heat treatments with high temperature values transformed the films into VO2 and V2O5 mixed-phase crystal structures. Due to the heat treatment carried out in the atmosphere and the high oxygen affinity of the vanadium metal, crystallization took place in both VO2 and V2O5 forms. In order to obtain homogeneous crystalline VO2 structures, heat treatments should be carried out for a long time in oxygen-limited environments.

Electrodeposited Fe2CoSn Thin Film with Enhanced Structural and Magnetic Properties

Single-phase near-stoichiometric Fe2CoSn Heusler alloy thin film of thickness 320 nm and crystallite size of 22 ± 1 nm was electrodeposited on low-cost Cu substrate. Heat-treated Fe2CoSn film exhibited an X-type inverse Heusler alloy structure along with high saturation magnetization (∼5 μ B/f.u.), high effective anisotropy constant (∼106 erg/cc), and high Curie temperature (983 K). Apart from demonstrating a procedure to obtain considerably thin electrodeposited Fe2CoSn films with high crystalline order, the electronic density of states close to the Fermi level have also been evaluated for its stable structure for the first time.

Physical properties of Fe–Ag–Pt films

Data are presented on the effect of high-frequency three-electrode ion-plasma sputtering and modernized three-electrode ion-plasma sputtering of a Fe–Ag–Pt complex target on the structure and properties of deposited films. The formation of nanocrystalline films with a size of the coherent scattering region of 3.5 nm during high-frequency ion-plasma spraying has been established. With the modernized three-electrode ion-plasma sputtering, a nanocrystalline phase is formed with a coherent scattering region size of 3 nm and higher temperature stability, up to 660 K. There were investigated the thermal stability of the metastable states of the Fe–Ag–Pt films; the electro- and hysteresis magnetic properties of freshly prepared and heat-treated films. The conditions for obtaining films with low values of the temperature coefficient of electrical resistance (∼5 × 10−5 K−1) and coercive force (Hc ∼ 12 kA/m) are determined.

Influence of growth time on the properties of CdTe thin films grown by electrodeposition using acetate precursor for solar energy application

Cadmium telluride (CdTe) thin films were deposited using a two–electrode electrodeposition (ED) configuration from an aqueous acidic solution. The electrolyte solution contains 1 M of cadmium acetate dihydrate (Cd (CH3OO) 2.2H2O) as cadmium precursor and 1 ml of tellurium dioxide (TeO2) as tellurium precursor. The thin films were grown for different deposition times of 60, 120, 180, 240, and 300 min to investigate the effect of the deposition period on the structural, optical, electrical, surface morphology, elemental composition, and surface roughness properties of the CdTe thin films in both as–deposited and heat–treated forms. X-ray diffraction (XRD) analysis indicates that the CdTe thin films have polycrystalline cubic zinc blend, orthorhombic and hexagonal structures. The result confirmed that the cubic phase is dominant and the peak for preferred orientation is along the (111) plane. Ultraviolet-visible (UV–vis) spectrophotometry study shows that the band gap of the as-deposited thin films varies from (1.41–1.45) eV, and after heat treatment, the band gap decreased to (1.39–1.42) eV. Photoelectrochemical cell (PEC) measurements show that CdTe thin films haven-type conductivity in both as–deposited and annealed forms. Scanning electron microscopy (SEM) analysis shows that the surface morphology of CdTe thin films changed as the deposition period increases. After heat treatment, increase in grain size was observed. Energy–dispersive x-ray spectroscopy (EDS) analysis shows that the percentage composition of as–deposited and heat-treated CdTe thin films varied with deposition time. After post–deposition treatment (PDT), the concentration of Te decreased, while that of Cd increased due to recrystallization during annealing. For the film deposited for 120 min, stoichiometric composition of CdTe was observed after heat treatment. Scanning probe microscopy (SPM) measurements revealed that the average surface roughness of the thin films varied with deposition time. The maximum average surface roughness was recorded when the film was deposited for 120 min. These results show that the prepared CdTe thin films have potential application as absorber layers in thin film solar cells.

Structural, morphological and ammonia sensing properties of spray deposited CeO2 films

CeO2 films is formed onto glass substrates by simple spray deposition technique using pyrolytic reaction of cerium nitrate hexahydrate which is termed as as-deposited film and the CeO2 film which is kept in furnace at 350 °C in the air atmosphere for 120 min is termed as heat treated film. The characteristics like structural, spectral, morphological and optical of both the films are studied. The structural analysis affirms that both the films are in cubic structure with polycrystalline nature. Uniform spherical shaped morphology is observed by SEM. The heat-treated film is chosen for the analysis of sensing characteristics for ammonia vapour with various concentrations (0.5–100 ppm) at room temperature. The better sensing performance with fast response and recovery times are achieved for 25 ppm of NH3. The room temperature response, fast transition time and perfect repeatability are achieved for low concentration (0.5 ppm) of NH3.

Characterization of heat-treated chitosan cast films and their antimicrobial activity on the growth of natural flora of pasteurized milk

This research aimed to evaluate the physicochemical and biocidal properties of chitosan films obtained through the solvent casting method using two different molecular weights, and thermally treated for an extended time (3 weeks) at 70 °C under vacuum condition (RH 0 %). The effect of storage time (for 30 and 180 days) under ambient conditions (23 °C and RH 40 %) on the properties of heat-treated cast films and their biocidal effectiveness was also assessed. FTIR-ATR, TGA and XRD of resulting films were analyzed to explore the dependency of antibacterial performance on the alteration in molecular and chemical structure. The results demonstrated that the solubility of treated films at 70 °C was proportionally reduced, resulting from the reduction of protonated amines and an increase in crystallinity. Likewise, increasing storage time led to a significant lowering in the solubilization of cast films. It was found that the solubilized fraction of chitosan cast films is the active fraction with the biocide behavior that can act against bacteria. In addition, the effectiveness of migrated chitosan was examined against the natural flora of pasteurized milk, such as Paenibacillus and Pseudomonas fluorescens. The results showed that cast films obtained from chitosan with lower molecular weight caused a reduction in the total count of viable cells without a significant effect on the properties of milk.

Effect of heat treatment on the structure and electromagnetic properties of FeSiAl films

FeSiAl films were prepared by magnetron sputtering and heat-treated in different atmospheres. The films were characterized by SEM, XRD, XPS, VSM and VNA. Relationship between the composition, microstructure and static magnetic and electromagnetic properties of FeSiAl films was investigated. The results showed that an insulating oxide layer was formed on the surface of heat-treated FeSiAl films. The oxide layer significantly affects the resistivity, saturation magnetization strength and electromagnetic properties of films. The films heat-treated in vacuum show relatively high resistivity and excellent electromagnetic properties with saturation magnetization strength of 2190 emu/cm3 and resistivity of 250.5 μΩ/cm. The ferromagnetic resonance frequency of the film is 1.8 GHz. The extrema of the imaginary part of the complex permeability reaches 1699, which is nearly 7.4 times higher than that of the as-deposited FeSiAl film, showing excellent microwave attenuation performance.

Comparison of Al3+ and Li+ liquid electrolytes for as deposited and heat treated WO3 thin films for electrochromic applications

Al3+ is considered as one of the alternative charge carrier ions to Li+ for WO3 based electrochromic (EC) devices. In this study, WO3 films have been grown by Magnetron Sputtering method and tested in Li+ and Al3+ liquid electrolytes for the comparison of EC performances. In order to see the effects of structure and heat treatment on the EC performance of WO3 films in both liquid electrolytes, films were annealed at 250°C, 350°C and 450°C. As deposited film and films heat treated up to 350°C were amorphous while the film annealed at 450°C crystallized. Surface modifications were observed with annealing, especially for the film annealed at 450 °C. X-ray photoelectron spectroscopic analysis indicated that the binding energies of W 4f did not vary much with annealing. However, noticeable changes were observed after the EC test performed on the WO3 films in trivalent Al3+ compared to the films tested in monovalent Li+ liquid electrolyte. The optic transmittance of the pristine and annealed films was basically the same except the film annealed at 450 °C for which the transmittance decreased by 25%. The Li+ ions have higher insertion and extraction in and out of the annealed films except the film annealed at 450 °C. The optical modulation parameter was highest for the film annealed at 350 °C tested in Al3+ while that of the pristine film was the highest for the films tested in Li+ electrolyte. The diffusion coefficients of Al3+ ions is calculated to be smaller compared to Li+ ions. The WO3 film annealed at 350 °C was found to be the most durable when tested in Al3+ while both pristine and heat-treated films had relatively better long-time durability for the cycle times used.