435563077da1fb082a07bfddc8968400.ppt
- Количество слайдов: 69
Advances In Characterization Techniques Dr. Krishna Gupta Technical Director Porous Materials, Inc. , USA PMI EUROPE WORK SHOP
Topics F Flow Porometry ê Accuracy and Reproducibility ê Technology for Characterization under ê ê Application Environment Directional Porometry Clamp-On Porometry Flexibility to Accommodate Samples of Wide Variety of Shapes, Sizes and Porosity Ease of Operation PMI EUROPE WORK SHOP
Topics F Permeametry ê ê Diffusion Gas Permeametry High Flow Gas Permeametry Microflow liquid permeametry High flow liquid permeametry at high temperature & high presure ê Envelope surface area, average particle size & average fiber diameter analysis ê Water vapor transmission rate PMI EUROPE WORK SHOP
Topics F Mercury Intrusion Porosimetry ê Stainless steel sample chamber ê Special design to minimize contact with mercury F Non-Mercury Intrusion Porosimetry ê Sample chamber that permits mercury intrusion porosimeter to be used as non-mercury intrusion porosimeter ê Water Intrusion Porosimeter PMI EUROPE WORK SHOP
Topics F Gas Adsorption F Conclusions PMI EUROPE WORK SHOP
Flow Porometry (Capillary Flow Porometry) Accuracy and Reproducibility F Most important sources of random & systematic errors identified F Design modified to minimized errors F Appropriate corrections incorporated PMI EUROPE WORK SHOP
Flow Porometry (Capillary Flow Porometry) Accuracy PMI EUROPE WORK SHOP
Flow Porometry (Capillary Flow Porometry) Repeatability F Bubble point repeated 32 times F Same operator F Same machine F Same wetting liquid F Same filter PMI EUROPE WORK SHOP
Flow Porometry (Capillary Flow Porometry) Filter Wetting Liquid Porewick Silwick Sintered Stainless Steel 1. 8% 1. 2% Battery Separator Paper 0. 2% 1. 7% 1. 5% 1. 1% PMI EUROPE WORK SHOP
Flow Porometry (Capillary Flow Porometry) F Errors due to the use of different machines Machine Bubble point Standard Deviation from pore diameter, deviation average of all Mean Value, mm machines 1 18. 35 0. 53% -1. 34% 2 18. 78 0. 48% 0. 93% 3 4 18. 37 18. 63 2. 34% 0. 75% 0. 28% 0. 13% PMI EUROPE WORK SHOP
Flow Porometry (Capillary Flow Porometry) F Operator errors Machine 1 Average of Difference between mean, mm mean values by operators mm Percentages 18. 38 0. 058 0. 32% 2 3 18. 77 0. 005 0. 222 4 18. 73 0. 213 1. 14% PMI EUROPE WORK SHOP 0. 03% 1. 19%
Technology for Characterization under Simulated Application Environment Compressive Stress F Arrangement for testing sample under compressive stress PMI EUROPE WORK SHOP
Technology for Characterization under Simulated Application Environment Compressive Stress Features: F Any compressive stress up to 1000 psi (700 k. Pa) F Sample size as large as 8 inches F Programmed to apply desired stress, perform test & release stress PMI EUROPE WORK SHOP
Technology for Characterization under Simulated Application Environment Effect of compressive stress on bubble point pore diameter PMI EUROPE WORK SHOP
Technology for Characterization under Simulated Application Environment PMI EUROPE WORK SHOP
Technology for Characterization under Simulated Application Environment Cyclic stress F Stress cycles are applied on sample sandwiched between two porous plates and the sample is tested during a pause in the stress cycle PMI EUROPE WORK SHOP
Technology for Characterization under Simulated Application Environment Sample chamber for cyclic compression porometer PMI EUROPE WORK SHOP
Technology for Characterization under Simulated Application Environment Features: F Any desired stress between 15 and 3000 psi F Stress may be applied and released at fixed rates F Duration of cycle 10 s F Frequency adjustable by changing the duration of application of stress PMI EUROPE WORK SHOP
Technology for Characterization under Simulated Application Environment Features: F Programmed to interrupt after specified number of cycles, wait for a predetermined length of time, measure characteristics and then continue stressing PMI EUROPE WORK SHOP
Technology for Characterization under Simulated Application Environment Features: F Sample can be tested any required number of times within a specified range F Fully automated PMI EUROPE WORK SHOP
Technology for Characterization under Simulated Application Environment Change of bubble point pore diameter with number of stress cycles PMI EUROPE WORK SHOP
Technology for Characterization under Simulated Application Environment Effects of Cyclic compression on permeability PMI EUROPE WORK SHOP
Technology for Characterization under Simulated Application Environment Aggressive environment Pore size of separator determined using KOH solution PMI EUROPE WORK SHOP
Technology for Characterization under Simulated Application Environment Directional Porometry F In this technique, Gas is allowed to displace liquid in pores in the specified direction PMI EUROPE WORK SHOP
Technology for Characterization under Simulated Application Environment Sample chamber for determination of in-plane (x-y plane) pore structure PMI EUROPE WORK SHOP
Technology for Characterization under Simulated Application Environment Sample chamber for determination of pore structure in a specific direction such as x or y PMI EUROPE WORK SHOP
Technology for Characterization under Simulated Application Environment Bubble point, mm Mean flow pore diameter, mm z-direction x-direction 14. 1 14. 6 1. 92 1. 04 y-direction 7. 60 0. 57 z-direction 12. 4 4. 20 x-y plane 1. 11 0. 09 z-direction 80. 4 ― x-y plane 43. 3 ― z-direction 34. 5 ― x-y plane 15. 3 Material Fuel cell component Printer Paper Transmission fluid filter felt Liquid filter ― PMI EUROPE WORK SHOP
Clamp-On Porometry F Sample chamber clamps on any desired location of sample (No need to cut sample & damage the material) Typical chambers for clamp-on porometer PMI EUROPE WORK SHOP
Clamp-On Porometry Advantages: F Very fast F No damage to the bulk material F Test may be performed on any location in the bulk material PMI EUROPE WORK SHOP
Flexibility to Accommodate a Wide Variety of Sample Shape, Size and Porosity Shapes: F Sheets F Plates F Discs F Rods F Tubes F Powders F Hollow Fibers F Pen tips F Cartridges F Diapers F Odd shapes F Nanofibers PMI EUROPE WORK SHOP
Flexibility to Accommodate a Wide Variety of Sample Shape, Size and Porosity Size: F Micron size biomedical devices F 8 inch wafers F Two feet cartridges F Entire diaper PMI EUROPE WORK SHOP
Flexibility to Accommodate a Wide Variety of Sample Shape, Size and Porosity Materials: F Ceramics F Metals F Textiles F Sponges F Nonwovens F Composites F Gels F Hydrogels PMI EUROPE WORK SHOP
Ease of Operation F Fully automated ê Test execution ê Data storage ê Data Reduction F User friendly interface F Menu driven windows based software PMI EUROPE WORK SHOP
Ease of Operation F Graphical display of real time test status and results of test in progress F Many user specified formats for plotting & display of results F Minimal operator involvement PMI EUROPE WORK SHOP
Advanced Permeametry Capability: F A wide variety of gases, liquids & strong chemicals F Different directions; x, y and z directions, x-y plane F At elevated temperatures, high pressure & under stress F Very low or very high permeability PMI EUROPE WORK SHOP
Diffusion Gas Permeametry Principle of diffusion permeameter PMI EUROPE WORK SHOP
Diffusion Gas Permeameter The PMI Diffusion Permeameter PMI EUROPE WORK SHOP
Diffusion Gas Permeametry Change of outlet gas pressure with time for two samples measured in the PMI Diffusion Permeameter. (d. Vs/dt) = (Ts. Vo/Tps)(dp/dt) Vs = gas flow in volume of gas at STP Vo = volume of chamber on the outlet side PMI Flow rate < 0. 75 x 10 -4 cm 3/s. EUROPE WORK SHOP
High Flow Gas Permeametry F Uses actual component; Diaper, Cartridges, etc. F Can measure flow rates as high as 105 cm 3/s F Can test large size components PMI EUROPE WORK SHOP
High Flow Gas Permeametry PMI High Flow Gas Permeameter PMI EUROPE WORK SHOP
Microflow Liquid Permeametry F Measures very low liquid permeability in materials ê Ceramic discs ê Membranes ê Potatoes ê Other vegetables & fruit F Uses a microbalance to measure small weights of displaced liquid, 10 -4 cm 3/s PMI EUROPE WORK SHOP
High Flow Liquid Permeametry at High Temperatures and High Pressures F Measures high permeability of application fluids at high temperature through actual parts under compressive stress PMI EUROPE WORK SHOP
High Flow Liquid Permeametry at High Temperatures and High Pressures The PMI high pressure, high temperature and high flow liquid permeameter PMI EUROPE WORK SHOP
High Flow Liquid Permeametry at High Temperatures and High Pressures Capability: F Temperature 100 C F Compressive stress on sample 300 psi F Liquid: Oil F Flow rate: 2 L/min PMI EUROPE WORK SHOP
Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement The PMI Envelope Surface Area, Average Fiber Diameter and Average Particle Size Analyzer PMI EUROPE WORK SHOP
Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement Envelope Surface Area F Computes surface area from flow rate using Kozeny and Carman relation PMI EUROPE WORK SHOP
Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement Envelope Surface Area F [Fl/p. A] ={P 3/[K(1 -P)2 S 2 m]}+[ZP 2 p]/[(1 P)S(2 ppr)1/2] F = gas flow rate in volume at average pressure, p l = thickness of sample per unit time p = pressure drop, (pi-po) p = average pressure, [(pi+po)/2], where pi is the inlet rb = bulk density of sample pressure and po is the outlet pressure ra = true density of sample A = cross-sectional area of sample m = viscosity of gas P = porosity (pore volume/total volume) = [1 -(rb/ra)] p = average pressure, [(pi+po)/2], where pi is the r = density of the gas at inlet pressure and po is the outlet pressure the average pressure, p S = through pore surface area per unit volume Z = a constant. It is shown to of solid in the sample be (48/13 p) K = a constant dependent on the geometry of the pores in the PMI EUROPE WORK SHOP media. It has a value close to 5 for random pored media
Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement F Comparison between BET and ESA Methods Sample ID ESA surface area (m^2/g) BET surface area (m^2/g) ESA particle size (microns) BET particle size (microns) Magnesium stearate A 11. 13 12. 16 0. 43 0. 39 Magnesium stearate B 6. 97 7. 13 0. 69 0. 67 Glass bubbles A Glass bubbles B 0. 89 0. 915 14. 82 14. 83 1. 76 1. 91 22. 25 20. 53 PMI EUROPE WORK SHOP
Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement Average particle size F Computes from surface area assuming same size & spherical shape of particles 6 d= Sr d = the average particle size S = specific surface area of the sample (total Surface area/mass) r = true density of the material PMI EUROPE WORK SHOP
Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement F Comparison between BET and ESA Methods Sample ID ESA surface area (m^2/g) BET surface area (m^2/g) ESA particle size (microns) BET particle size (microns) Magnesium stearate A 11. 13 12. 16 0. 43 0. 39 Magnesium stearate B 6. 97 7. 13 0. 69 0. 67 Glass bubbles A Glass bubbles B 0. 89 0. 915 14. 82 14. 83 1. 76 1. 91 22. 25 20. 53 PMI EUROPE WORK SHOP
Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement Average fiber diameter F Computed from flow rate using Davies equation F (4 p. AR 2)/(m. Fl) = 64 c 1. 5[1+52 c 3] P 0. 7 -0. 99 c = packing density (ratio of volume of fibers to volume of sample) = (1 -P) p = pressure gradient A = cross-sectional area of sample R = average fiber radius m = viscosity of gas F = gas flow rate average pressure PMI EUROPE WORK SHOP L = thickness of sample
Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement Measured fiber diameters in microns plotted against the actual fiber diameters PMI EUROPE WORK SHOP
Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement F Average fiber diameter can also be computed from the envelope surface area. Assuming the fibers to have the same radius and the same length; Df = 4 V/S = 4/Sr Df = average fiber diameter V = volume of fibers per unit mass S = envelope surface area of fibers per unit mass r = true density of fibers PMI EUROPE WORK SHOP
Water Vapor Transmission under pressure gradient Principle of Water vapor transmission analyzer PMI EUROPE WORK SHOP
Water Vapor Transmission under pressure gradient Change of pressure on the outlet side of two samples of the naphion membrane in the PMI Water Vapor Transmission Analyzer PMI EUROPE WORK SHOP
Water Vapor Transmission under concentration gradient Line diagram showing the operating principle of PMI Advanced Water Vapor Transmission Analyzer PMI EUROPE WORK SHOP
Water Vapor Transmission under concentration gradient Water vapor transmission rate through several samples PMI EUROPE WORK SHOP
Mercury Intrusion Porosimetry Stainless Steel Sample Chamber of The PMI Mercury Intrusion Porosimeter PMI EUROPE WORK SHOP
Mercury Intrusion Porosimetry Special design to minimize contact with mercury The PMI Mercury Intrusion Porosimeter PMI EUROPE WORK SHOP
Mercury Intrusion Porosimetry F Separation of high-pressure section from low-pressure section F Sample chamber is evacuated and pressurized without transferring the chamber and contacting mercury F Automatic cleaning of the system by evacuation PMI EUROPE WORK SHOP
Mercury Intrusion Porosimetry F Automatic refilling of penetrometer by mercury F Automatic drainage of mercury F In-situ pretreatment of the sample F Fully automated operation PMI EUROPE WORK SHOP
Non-Mercury Intrusion Prosimetry Sample Chamber That permits Mercury Intrusion Porosimeter to be used as a Non-Mercury Intrusion Porosimeter Sample Chamber for use to perform non-mercury intrusion tests in the PMI Mercury Intrusion Porosimeter PMI EUROPE WORK SHOP
Water Intrusion Porosimeter (Aquapore) F Uses absolutely no mercury F Water used as intrusion liquid F Can test hydrophobic materials F Can detect hydrophobic pores in a mixture PMI EUROPE WORK SHOP
Water Intrusion Porosimeter (Aquapore) The PMI Aquapore PMI EUROPE WORK SHOP
Gas Adsorption F A new technique developed by PMI F Capable of very fast measurement (<10 min) of single point and multipoint surface areas F The PMI QBET for fast surface area measurement PMI EUROPE WORK SHOP
Conclusions F Recent advances made in the technology of measurement and novel methods of measurement of properties using porometry, permeametry, porosimetry and gas adsorption have been discussed PMI EUROPE WORK SHOP
Conclusions F Results have been presented to show the improvements in accuracy and repeatability of results and ease of operation of the test. PMI EUROPE WORK SHOP
Conclusions F Measurement of characteristics under application environments involving: ê compressive stress ê cyclic compression ê aggressive conditions ê elevated temperatures ê high pressures have been illustrated with examples PMI EUROPE WORK SHOP
Thank You PMI EUROPE WORK SHOP